Taiwan

total: 1,582 km

standard gauge: 345 km 1.435-m gauge

narrow gauge: 1,091 km 1.067-m gauge; 146 km .762-m gauge

note: the 146 km of .762 gauge track belongs primarily to Taiwan

Sugar Corporation and Taiwan Forestry Bureau, some to other entities

(2008)

Tajikistan

total: 680 km

broad gauge: 680 km 1.520-m gauge (2008)

Tanzania

total: 3,689 km

narrow gauge: 969 km 1.067-m gauge; 2,720 km 1.000-m gauge (2008)

Thailand

total: 4,071 km

standard gauge: 29 km 1.435-m gauge

narrow gauge: 4,042 km 1.000-m gauge (2008)

Togo

total: 532 km

narrow gauge: 532 km 1.000-m gauge (2008)

Tunisia

total: 2,167 km

standard gauge: 471 km 1.435-m gauge

narrow gauge: 1,688 km 1.000-m gauge (65 km electrified)

dual gauge: 8 km (2008)

Turkey

total: 8,697 km

standard gauge: 8,697 km 1.435-m gauge (1,920 km electrified) (2008)

Turkmenistan

total: 2,980 km

broad gauge: 2,980 km 1.520-m gauge (2008)

Uganda

total: 1,244 km

narrow gauge: 1,244 km 1.000-m gauge (2008)

Ukraine

total: 21,658 km

broad gauge: 21,658 km 1.524-m gauge (9,729 km electrified) (2009)

United Kingdom

total: 16,454 km

broad gauge: 303 km 1.600-m gauge (in Northern Ireland)

standard gauge: 16,151 km 1.435-m gauge (5,248 km electrified) (2008)

United States

total: 226,427 km

standard gauge: 226,427 km 1.435-m gauge (2007)

Uruguay

total: 1,641 km (1,200 km operational)

standard gauge: 1,641 km 1.435-m gauge (2010)

Uzbekistan

total: 3,645 km

broad gauge: 3,645 km 1.520-m gauge (620 km electrified) (2008)

Venezuela

total: 806 km

standard gauge: 806 km 1.435-m gauge (2008)

Vietnam

total: 2,347 km

standard gauge: 178 km 1.435-m gauge

narrow gauge: 2,169 km 1.000-m gauge (2008)

World

total: 1,138,632 km (2008)

Zambia

total: 2,157 km

narrow gauge: 2,157 km 1.067-m gauge

note: includes 891 km of the Tanzania-Zambia Railway Authority

(TAZARA) (2008)

Zimbabwe

total: 3,077 km

narrow gauge: 3,077 km 1.067-m gauge (313 km electrified) (2008)

======================================================================

@2122

Field Listing :: Religions

This entry is an ordered listing of religions by adherents starting

with the largest group and sometimes includes the percent of total

population. The core characteristics and beliefs of the world's

major religions are described below.

Baha'i - Founded by Mirza Husayn-Ali (known as Baha'u'llah) in Iran

in 1852, Baha'i faith emphasizes monotheism and believes in one

eternal transcendent God. Its guiding focus is to encourage the

unity of all peoples on the earth so that justice and peace may be

achieved on earth. Baha'i revelation contends the prophets of major

world religions reflect some truth or element of the divine,

believes all were manifestations of God given to specific

communities in specific times, and that Baha'u'llah is an additional

prophet meant to call all humankind. Bahais are an open community,

located worldwide, with the greatest concentration of believers in

South Asia.

Buddhism - Religion or philosophy inspired by the 5th century B.C.

teachings of Siddhartha Gautama (also known as Gautama Buddha "the

enlightened one"). Buddhism focuses on the goal of spiritual

enlightenment centered on an understanding of Gautama Buddha's Four

Noble Truths on the nature of suffering, and on the Eightfold Path

of spiritual and moral practice, to break the cycle of suffering of

which we are a part. Buddhism ascribes to a karmic system of

rebirth. Several schools and sects of Buddhism exist, differing

often on the nature of the Buddha, the extent to which enlightenment

can be achieved - for one or for all, and by whom - religious orders

or laity.

Basic Groupings

Theravada Buddhism: The oldest Buddhist school, Theravada is

practiced mostly in Sri Lanka, Cambodia, Laos, Burma, and Thailand,

with minority representation elsewhere in Asia and the West.

Theravadans follow the Pali Canon of Buddha's teachings, and believe

that one may escape the cycle of rebirth, worldly attachment, and

suffering for oneself; this process may take one or several

lifetimes.

Mahayana Buddhism, including subsets Zen and Tibetan Buddhism:

Forms of Mahayana Buddhism are common in East Asia and Tibet, and

parts of the West. Mahayanas have additional scriptures beyond the

Pali Canon and believe the Buddha is eternal and still teaching.

Unlike Theravada Buddhism, Mahayana schools maintain the

Buddha-nature is present in all beings and all will ultimately

achieve enlightenment.

Christianity - Descending from Judaism, Christianity's central

belief maintains Jesus of Nazareth is the promised messiah of the

Hebrew Scriptures, and that his life, death, and resurrection are

salvific for the world. Christianity is one of the three

monotheistic Abrahamic faiths, along with Islam and Judaism, which

traces its spiritual lineage to Abraham of the Hebrew Scriptures.

Its sacred texts include the Hebrew Bible and the New Testament (or

the Christian Gospels).

Basic Groupings

Catholicism (or Roman Catholicism): This is the oldest

established western Christian church and the world's largest single

religious body. It is supranational, and recognizes a hierarchical

structure with the Pope, or Bishop of Rome, as its head, located at

the Vatican. Catholics believe the Pope is the divinely ordered head

of the Church from a direct spiritual legacy of Jesus' apostle

Peter. Catholicism is comprised of 23 particular Churches, or Rites

- one Western (Roman or Latin-Rite) and 22 Eastern. The Latin Rite

is by far the largest, making up about 98% of Catholic membership.

Eastern-Rite Churches, such as the Maronite Church and the Ukrainian

Catholic Church, are in communion with Rome although they preserve

their own worship traditions and their immediate hierarchy consists

of clergy within their own rite. The Catholic Church has a

comprehensive theological and moral doctrine specified for believers

in its catechism, which makes it unique among most forms of

Christianity.

Mormonism (including the Church of Jesus Christ of Latter-Day

Saints): Originating in 1830 in the United States under Joseph

Smith, Mormonism is not characterized as a form of Protestant

Christianity because it claims additional revealed Christian

scriptures after the Hebrew Bible and New Testament. The Book of

Mormon maintains there was an appearance of Jesus in the New World

following the Christian account of his resurrection, and that the

Americas are uniquely blessed continents. Mormonism believes earlier

Christian traditions, such as the Roman Catholic, Orthodox, and

Protestant reform faiths, are apostasies and that Joseph Smith's

revelation of the Book of Mormon is a restoration of true

Christianity. Mormons have a hierarchical religious leadership

structure, and actively proselytize their faith; they are located

primarily in the Americas and in a number of other Western countries.

Orthodox Christianity: The oldest established eastern form of

Christianity, the Holy Orthodox Church, has a ceremonial head in the

Bishop of Constantinople (Istanbul), also known as a Patriarch, but

its various regional forms (e.g., Greek Orthodox, Russian Orthodox,

Serbian Orthodox, Ukrainian Orthodox) are autocephalous (independent

of Constantinople's authority, and have their own Patriarchs).

Orthodox churches are highly nationalist and ethnic. The Orthodox

Christian faith shares many theological tenets with the Roman

Catholic Church, but diverges on some key premises and does not

recognize the governing authority of the Pope.

Protestant Christianity: Protestant Christianity originated in

the 16th century as an attempt to reform Roman Catholicism's

practices, dogma, and theology. It encompasses several forms or

denominations which are extremely varied in structure, beliefs,

relationship to state, clergy, and governance. Many protestant

theologies emphasize the primary role of scripture in their faith,

advocating individual interpretation of Christian texts without the

mediation of a final religious authority such as the Roman Pope. The

oldest Protestant Christianities include Lutheranism, Calvinism

(Presbyterians), and Anglican Christianity (Episcopalians), which

have established liturgies, governing structure, and formal clergy.

Other variants on Protestant Christianity, including Pentecostal

movements and independent churches, may lack one or more of these

elements, and their leadership and beliefs are individualized and

dynamic.

Hinduism - Originating in the Vedic civilization of India (second

and first millennium B.C.), Hinduism is an extremely diverse set of

beliefs and practices with no single founder or religious authority.

Hinduism has many scriptures; the Vedas, the Upanishads, and the

Bhagavad-Gita are among some of the most important. Hindus may

worship one or many deities, usually with prayer rituals within

their own home. The most common figures of devotion are the gods

Vishnu, Shiva, and a mother goddess, Devi. Most Hindus believe the

soul, or atman, is eternal, and goes through a cycle of birth,

death, and rebirth (samsara) determined by one's positive or

negative karma, or the consequences of one's actions. The goal of

religious life is to learn to act so as to finally achieve

liberation (moksha) of one's soul, escaping the rebirth cycle.

Islam - The third of the monotheistic Abrahamic faiths, Islam

originated with the teachings of Muhammad in the 7th century.

Muslims believe Muhammad is the final of all religious prophets

(beginning with Abraham) and that the Qu'ran, which is the Islamic

scripture, was revealed to him by God. Islam derives from the word

submission, and obedience to God is a primary theme in this

religion. In order to live an Islamic life, believers must follow

the five pillars, or tenets, of Islam, which are the testimony of

faith (shahada), daily prayer (salah), giving alms (zakah), fasting

during Ramadan (sawm), and the pilgrimage to Mecca (hajj).

Basic Groupings

The two primary branches of Islam are Sunni and Shia, which split

from each other over a religio-political leadership dispute about

the rightful successor to Muhammad. The Shia believe Muhammad's

cousin and son-in-law, Ali, was the only divinely ordained Imam

(religious leader), while the Sunni maintain the first three caliphs

after Muhammad were also legitimate authorities. In modern Islam,

Sunnis and Shia continue to have different views of acceptable

schools of Islamic jurisprudence, and who is a proper Islamic

religious authority. Islam also has an active mystical branch,

Sufism, with various Sunni and Shia subsets.

Sunni Islam accounts for over 75% of the world's Muslim

population. It recognizes the Abu Bakr as the first caliph after

Muhammad. Sunni has four schools of Islamic doctrine and law -

Hanafi, Maliki, Shafi'i, and Hanbali - which uniquely interpret the

Hadith, or recorded oral traditions of Muhammad. A Sunni Muslim may

elect to follow any one of these schools, as all are considered

equally valid.

Shia Islam represents 10-20% of Muslims worldwide, and its

distinguishing feature is its reverence for Ali as an infallible,

divinely inspired leader, and as the first Imam of the Muslim

community after Muhammad. A majority of Shia are known as

"Twelvers," because they believe that the 11 familial successor

imams after Muhammad culminate in a 12th Imam (al-Mahdi) who is

hidden in the world and will reappear at its end to redeem the

righteous.

Variants

Ismaili faith: A sect of Shia Islam, its adherents are also known

as "Seveners," because they believe that the rightful seventh Imam

in Islamic leadership was Isma'il, the elder son of Imam Jafar

al-Sadiq. Ismaili tradition awaits the return of the seventh Imam as

the Mahdi, or Islamic messianic figure. Ismailis are located in

various parts of the world, particularly South Asia and the Levant.

Alawi faith: Another Shia sect of Islam, the name reflects

followers' devotion to the religious authority of Ali. Alawites are

a closed, secretive religious group who assert they are Shia

Muslims, although outside scholars speculate their beliefs may have

a syncretic mix with other faiths originating in the Middle East.

Alawis live mostly in Syria, Lebanon, and Turkey.

Druze faith: A highly secretive tradition and a closed community

that derives from the Ismaili sect of Islam; its core beliefs are

thought to emphasize a combination of Gnostic principles believing

that the Fatimid caliph, al-Hakin, is the one who embodies the key

aspects of goodness of the universe, which are, the intellect, the

word, the soul, the preceder, and the follower. The Druze have a key

presence in Syria, Lebanon, and Israel.

Jainism - Originating in India, Jain spiritual philosophy believes

in an eternal human soul, the eternal universe, and a principle of

"the own nature of things." It emphasizes compassion for all living

things, seeks liberation of the human soul from reincarnation

through enlightenment, and values personal responsibility due to the

belief in the immediate consequences of one's behavior. Jain

philosophy teaches non-violence and prescribes vegetarianism for

monks and laity alike; its adherents are a highly influential

religious minority in Indian society.

Judaism - One of the first known monotheistic religions, likely

dating to between 2000-1500 B.C., Judaism is the native faith of the

Jewish people, based upon the belief in a covenant of responsibility

between a sole omnipotent creator God and Abraham, the patriarch of

Judaism's Hebrew Bible, or Tanakh. Divine revelation of principles

and prohibitions in the Hebrew Scriptures form the basis of Jewish

law, or halakhah, which is a key component of the faith. While there

are extensive traditions of Jewish halakhic and theological

discourse, there is no final dogmatic authority in the tradition.

Local communities have their own religious leadership. Modern

Judaism has three basic categories of faith: Orthodox, Conservative,

and Reform/Liberal. These differ in their views and observance of

Jewish law, with the Orthodox representing the most traditional

practice, and Reform/Liberal communities the most accommodating of

individualized interpretations of Jewish identity and faith.

Shintoism - A native animist tradition of Japan, Shinto practice is

based upon the premise that every being and object has its own

spirit or kami. Shinto practitioners worship several particular

kamis, including the kamis of nature, and families often have

shrines to their ancestors' kamis. Shintoism has no fixed tradition

of prayers or prescribed dogma, but is characterized by individual

ritual. Respect for the kamis in nature is a key Shinto value. Prior

to the end of World War II, Shinto was the state religion of Japan,

and bolstered the cult of the Japanese emperor.

Sikhism - Founded by the Guru Nanak (born 1469), Sikhism believes in

a non-anthropomorphic, supreme, eternal, creator God; centering

one's devotion to God is seen as a means of escaping the cycle of

rebirth. Sikhs follow the teachings of Nanak and nine subsequent

gurus. Their scripture, the Guru Granth Sahib - also known as the

Adi Granth - is considered the living Guru, or final authority of

Sikh faith and theology. Sikhism emphasizes equality of humankind

and disavows caste, class, or gender discrimination.

Taoism - Chinese philosophy or religion based upon Lao Tzu's Tao Te

Ching, which centers on belief in the Tao, or the way, as the flow

of the universe and the nature of things. Taoism encourages a

principle of non-force, or wu-wei, as the means to live harmoniously

with the Tao. Taoists believe the esoteric world is made up of a

perfect harmonious balance and nature, while in the manifest world -

particularly in the body - balance is distorted. The Three Jewels of

the Tao - compassion, simplicity, and humility - serve as the basis

for Taoist ethics.

Zoroastrianism - Originating from the teachings of Zoroaster in

about the 9th or 10th century B.C., Zoroastrianism may be the oldest

continuing creedal religion. Its key beliefs center on a

transcendent creator God, Ahura Mazda, and the concept of free will.

The key ethical tenets of Zoroastrianism expressed in its scripture,

the Avesta, are based on a dualistic worldview where one may prevent

chaos if one chooses to serve God and exercises good thoughts, good

words, and good deeds. Zoroastrianism is generally a closed religion

and members are almost always born to Zoroastrian parents. Prior to

the spread of Islam, Zoroastrianism dominated greater Iran. Today,

though a minority, Zoroastrians remain primarily in Iran, India, and

Pakistan.

Country

Religions(%)

Afghanistan

Sunni Muslim 80%, Shia Muslim 19%, other 1%

Albania

Muslim 70%, Albanian Orthodox 20%, Roman Catholic 10%

note: percentages are estimates; there are no available current

statistics on religious affiliation; all mosques and churches were

closed in 1967 and religious observances prohibited; in November

1990, Albania began allowing private religious practice

Algeria

Sunni Muslim (state religion) 99%, Christian and Jewish 1%

American Samoa

Christian Congregationalist 50%, Roman Catholic 20%,

Protestant and other 30%

Andorra

Roman Catholic (predominant)

Angola

indigenous beliefs 47%, Roman Catholic 38%, Protestant 15%

(1998 est.)

Anguilla

Anglican 29%, Methodist 23.9%, other Protestant 30.2%,

Roman Catholic 5.7%, other Christian 1.7%, other 5.2%, none or

unspecified 4.3% (2001 census)

Antigua and Barbuda

Anglican 25.7%, Seventh Day Adventist 12.3%,

Pentecostal 10.6%, Moravian 10.5%, Roman Catholic 10.4%, Methodist

7.9%, Baptist 4.9%, Church of God 4.5%, other Christian 5.4%, other

2%, none or unspecified 5.8% (2001 census)

Argentina

nominally Roman Catholic 92% (less than 20% practicing),

Protestant 2%, Jewish 2%, other 4%

Armenia

Armenian Apostolic 94.7%, other Christian 4%, Yezidi

(monotheist with elements of nature worship) 1.3%

Aruba

Roman Catholic 80.8%, Evangelist 4.1%, Protestant 2.5%,

Jehovah's Witnesses 1.5%, Methodist 1.2%, Jewish 0.2%, other 5.1%,

none or unspecified 4.6%

Australia

Catholic 25.8%, Anglican 18.7%, Uniting Church 5.7%,

Presbyterian and Reformed 3%, Eastern Orthodox 2.7%, other Christian

7.9%, Buddhist 2.1%, Muslim 1.7%, other 2.4%, unspecified 11.3%,

none 18.7% (2006 Census)

Austria

Roman Catholic 73.6%, Protestant 4.7%, Muslim 4.2%, other

3.5%, unspecified 2%, none 12% (2001 census)

Azerbaijan

Muslim 93.4%, Russian Orthodox 2.5%, Armenian Orthodox

2.3%, other 1.8% (1995 est.)

note: religious affiliation is still nominal in Azerbaijan;

percentages for actual practicing adherents are much lower

Bahamas, The

Baptist 35.4%, Anglican 15.1%, Roman Catholic 13.5%,

Pentecostal 8.1%, Church of God 4.8%, Methodist 4.2%, other

Christian 15.2%, none or unspecified 2.9%, other 0.8% (2000 census)

Bahrain

Muslim (Shia and Sunni) 81.2%, Christian 9%, other 9.8%

(2001 census)

Bangladesh

Muslim 89.5%, Hindu 9.6%, other 0.9% (2004)

Barbados

Protestant 63.4% (Anglican 28.3%, Pentecostal 18.7%,

Methodist 5.1%, other 11.3%), Roman Catholic 4.2%, other Christian

7%, other 4.8%, none or unspecified 20.6% (2008 est.)

Belarus

Eastern Orthodox 80%, other (including Roman Catholic,

Protestant, Jewish, and Muslim) 20% (1997 est.)

Belgium

Roman Catholic 75%, other (includes Protestant) 25%

Belize

Roman Catholic 49.6%, Protestant 27% (Pentecostal 7.4%,

Anglican 5.3%, Seventh-Day Adventist 5.2%, Mennonite 4.1%, Methodist

3.5%, Jehovah's Witnesses 1.5%), other 14%, none 9.4% (2000)

Benin

Christian 42.8% (Catholic 27.1%, Celestial 5%, Methodist 3.2%,

other Protestant 2.2%, other 5.3%), Muslim 24.4%, Vodoun 17.3%,

other 15.5% (2002 census)

Bermuda

Anglican 23%, Roman Catholic 15%, African Methodist

Episcopal 11%, other Protestant 18%, other 12%, unaffiliated 6%,

unspecified 1%, none 14% (2000 census)

Bhutan

Lamaistic Buddhist 75%, Indian- and Nepalese-influenced

Hinduism 25%

Bolivia

Roman Catholic 95%, Protestant (Evangelical Methodist) 5%

Bosnia and Herzegovina

Muslim 40%, Orthodox 31%, Roman Catholic 15%,

other 14%

Botswana

Christian 71.6%, Badimo 6%, other 1.4%, unspecified 0.4%,

none 20.6% (2001 census)

Brazil

Roman Catholic (nominal) 73.6%, Protestant 15.4%,

Spiritualist 1.3%, Bantu/voodoo 0.3%, other 1.8%, unspecified 0.2%,

none 7.4% (2000 census)

British Virgin Islands

Protestant 86% (Methodist 33%, Anglican 17%,

Church of God 9%, Seventh-Day Adventist 6%, Baptist 4%, Jehovah's

Witnesses 2%, other 15%), Roman Catholic 10%, other 2%, none 2%

(1991)

Brunei

Muslim (official) 67%, Buddhist 13%, Christian 10%, other

(includes indigenous beliefs) 10%

Bulgaria

Bulgarian Orthodox 82.6%, Muslim 12.2%, other Christian

1.2%, other 4% (2001 census)

Burkina Faso

Muslim 50%, indigenous beliefs 40%, Christian (mainly

Roman Catholic) 10%

Burma

Buddhist 89%, Christian 4% (Baptist 3%, Roman Catholic 1%),

Muslim 4%, animist 1%, other 2%

Burundi

Christian 67% (Roman Catholic 62%, Protestant 5%),

indigenous beliefs 23%, Muslim 10%

Cambodia

Buddhist 96.4%, Muslim 2.1%, other 1.3%, unspecified 0.2%

(1998 census)

Cameroon

indigenous beliefs 40%, Christian 40%, Muslim 20%

Canada

Roman Catholic 42.6%, Protestant 23.3% (including United

Church 9.5%, Anglican 6.8%, Baptist 2.4%, Lutheran 2%), other

Christian 4.4%, Muslim 1.9%, other and unspecified 11.8%, none 16%

(2001 census)

Cape Verde

Roman Catholic (infused with indigenous beliefs),

Protestant (mostly Church of the Nazarene)

Cayman Islands

Church of God 25.5%, Roman Catholic 12.6%,

Presbyterian / United Church 9.2%, Seventh Day Adventist 8.4%,

Baptist 8.3%, Pentecostal 6.7%, Anglican 3.9%, other religions 4%,

non-denominational 5.7%, other 6.5%, none 6.1%, unspecified 3.2%

(2007)

Central African Republic

indigenous beliefs 35%, Protestant 25%,

Roman Catholic 25%, Muslim 15%

note: animistic beliefs and practices strongly influence the

Christian majority

Chad

Muslim 53.1%, Catholic 20.1%, Protestant 14.2%, animist 7.3%,

other 0.5%, unknown 1.7%, atheist 3.1% (1993 census)

Chile

Roman Catholic 70%, Evangelical 15.1%, Jehovah's Witness 1.1%,

other Christian 1%, other 4.6%, none 8.3% (2002 census)

China

Daoist (Taoist), Buddhist, Christian 3%-4%, Muslim 1%-2%

note: officially atheist (2002 est.)

Christmas Island

Buddhist 36%, Muslim 25%, Christian 18%, other 21%

(1997)

Cocos (Keeling) Islands

Sunni Muslim 80%, other 20% (2002 est.)

Colombia

Roman Catholic 90%, other 10%

Comoros

Sunni Muslim 98%, Roman Catholic 2%

Congo, Democratic Republic of the

Roman Catholic 50%, Protestant

20%, Kimbanguist 10%, Muslim 10%, other (includes syncretic sects

and indigenous beliefs) 10%

Congo, Republic of the

Christian 50%, animist 48%, Muslim 2%

Cook Islands

Cook Islands Christian Church 55.9%, Roman Catholic

16.8%, Seventh-Day Adventists 7.9%, Church of Latter Day Saints

3.8%, other Protestant 5.8%, other 4.2%, unspecified 2.6%, none 3%

(2001 census)

Costa Rica

Roman Catholic 76.3%, Evangelical 13.7%, Jehovah's

Witnesses 1.3%, other Protestant 0.7%, other 4.8%, none 3.2%

Cote d'Ivoire

Muslim 38.6%, Christian 32.8%, indigenous 11.9%, none

16.7% (2008 est.)

note: the majority of foreigners (migratory workers) are Muslim

(70%) and Christian (20%)

Croatia

Roman Catholic 87.8%, Orthodox 4.4%, other Christian 0.4%,

Muslim 1.3%, other and unspecified 0.9%, none 5.2% (2001 census)

Cuba

nominally 85% Roman Catholic prior to CASTRO assuming power;

Protestants, Jehovah's Witnesses, Jews, and Santeria are also

represented

Curacao

Roman Catholic 80.1%, Protestant 5.5%, none 4.6%,

Pentecostal 3.5%, Seventh Day Adventist 2.2%, Jehovah's Witnesses

1.7%, Jewish 0.8%, other 1.3%, not reported 0.3% (2001 census)

Cyprus

Greek Orthodox 78%, Muslim 18%, other (includes Maronite and

Armenian Apostolic) 4%

Czech Republic

Roman Catholic 26.8%, Protestant 2.1%, other 3.3%,

unspecified 8.8%, unaffiliated 59% (2001 census)

The 2010 CIA World Factbook · 第 358 / 461 段