=====================================================================
| | | | Native |
| | | Native | white |
| Negroes | Mulattoes | white | of foreign| Foreign
| | | of native | or mixed | born white
| | | parentage | parentage |
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----
| M | F | M | F | M | F | M | F | M | F
---------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----
Under | | | | | | | | | |
5 years | 12.9| 11.6| 18.3| 17.4| 17.1| 16.4| 10.1| 8.9| .8| 2.1
5 to 24 | 42.3| 42.5| 48.2| 47.1| 46.2| 46.4| 45.6| 45.9| 18.8| 20.8
25 to 54 | 34.4| 34.8| 29. | 30.1| 31.7| 31.5| 36.6| 35.6| 64.6| 57.2
55 to 84 | 9.7| 10.5| 4.4| 5.3| 5. | 5. | 7.4| 9.3| 15.6| 19.2
85 years | | | | | | | | | |
and over | .7| .8| .1| .2| .1| .2| .1| .3| .2| .8
---------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----
It will be noticed that above the age of 55 there is a larger proportion
of women than men in each class. Judging the median age for each group
to be the year which divides the total number of that group into two
equal divisions, so far as number is concerned, we find the following
median ages: blacks, 23; mulattoes, 18; native whites of native
parentage, 20; native whites of foreign or mixed parentage, 22;
foreign-born whites, 37. These results correspond exactly with the
statements previously made regarding the longevity of each group. This
would, of course, only give the median age for each class at the time
the census was taken, in 1910, but as practically the same age
distribution is also found in the census of 1899, it may be concluded
that the results are approximately correct. This means that 50 per cent
of each group does not live beyond the age indicated, and is sometimes
known as the "mean length of life." Data for calculating the average
length of life are not available.
A comparison of the age groups in the United States and in Porto Rico
shows that the proportion in the younger ages is greater in Porto Rico
than it is in the United States.