Note: Estimates rounded to nearest 1,000.
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+Demographic techniques used to create prevalence estimates+
Estimates of the prevalence of ever having gone to prison were derived
from generation life table techniques. The prevalence of ever having
gone to prison includes adults currently in prison and living former
prisoners.
One-day counts of the number of adults in prison are available through
the National Prisoner Statistics program (NPS). Collected annually
since 1926, the NPS provides a count at yearend of persons held in
Federal and State prisons.
To obtain the number of persons who had ever gone to prison, separate
generation life tables were prepared for persons alive between 1974 and
2001. These tables model the first incarceration and mortality
experience of each birth cohort as it proceeded through life. Estimates
were made of the number of persons going to prison for the first time,
by year of age, and the number who had been incarcerated and survived
to each later age.
Rates of first incarceration during a 12-month period were developed
from prison inmate surveys conducted in 1974, 1979, 1986, 1991, and
1997, a period during which admission rates increased after many years
of relative stability.
Prevalence estimates for selected calendar years represent a sum of the
contribution of each birth cohort to the total number of adults alive
who had ever gone to prison. The number of former prisoners was
obtained by subtracting the number of prisoners at yearend (NPS) from
the total.
Estimates exclude admissions to local jails, due to the absence of data
needed to calculate first admissions to jail. (See Methodology for
estimation procedures and limitations.)
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+1 in 37 adult U.S. residents in 2001 had ever served time in prison+
The 5.6 million adult U.S. residents who were current and former
prisoners, represented an increase of 3.8 million since 1974. At
yearend 2001, 2,673 persons per 100,000 adult U.S. residents had ever
gone to prison, up from 1,251 per 100,000 adult residents in 1974.
Overall, approximately 1 in 37 adult residents in 2001 had ever served
time in a State or Federal prison.
As a percent of all adults who had ever gone to a State or Federal
prison, the number of former prisoners has steadily declined (from 88%
in 1974 to 77% in 2001). The decline occurred as the number of adults
confined in prison at yearend grew by 1.1 million -- a 6-fold increase.
Over the 27-year period the number of adult prison inmates rose from
216,000 to 1,319,000. By yearend 2001, there were 628 prison inmates
per 100,000 adult residents, up from 149 in 1974.
Between 1974 and 2001 the number of former prisoners living in the
United States more than doubled, from 1,603,000 to 4,299,000. Relative
to the adult population, the number of former prisoners totaled 2,045
per 100,000 adult U.S. residents in 2001, up from 1,102 per 100,000 in
1974. At yearend 2001, 1 in every 49 adults in the United States was a
former prisoner.
+Two-thirds of the increase in number ever incarcerated due to rise in
first incarceration rates+
Nearly two-thirds of the 3.8 million increase in the number of adults
ever incarcerated in prison between 1974 and 2001 occurred as a result
of an increase in the rates of first incarceration. In 1974 the number
of persons admitted to prison for the first time totaled 44 per 100,000
adult residents. By 2001 the rate had nearly tripled, reaching 129
first admissions per 100,000 adults.
Over 40% of the total increase in first incarceration rates occurred
between 1986 and 1991. First incarceration rates increased from 73 per
100,000 in 1986 to 111 in 1991.
About a third of the 3.8 million increase in the number ever
incarcerated occurred as a result of growth in the U.S. resident
population. Based on estimates from the U.S. Census Bureau, the number
of residents 18 and older increased from 145 million in 1974 to 210
million in 2001. Had the rates of first incarceration remained stable
at 1974 levels, the number of adults who had ever gone to prison would
have increased by an estimated 1.3 million.
In every year, the rates of first incarceration varied by age (figure
1). In 2001 sharply higher first incarceration rates were found for
each older birth cohort up to a peak of 350 per 100,000 at age 20.
These rates then dropped steadily with each older age category.
[Illustration: Figure 1: First incarceration rates]
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