70 19,778,402 ... 377,000
1930-1901 71 or older 23,755,091 ... 384,000

[a] The number of U.S. residents on December 31, 2001, by age, were
based on projections for July 1, 2000, and July 1, 2001.

(See Projections of the Resident Population by Age, Sex,, Race and
Hispanic Origin: 1999 to 2100, U.S. Census Bureau, NP-D1-A, middle
series.) The data were adjusted for the undercount in the 1990
decennial census.

[b] Based on separate generation life tables starting in the year of
birth of the persons at each year of age. (See Appendix tables 2
and 3 for calculations for selected years of birth.)

[c] Estimates were calculated by multiplying column (1) by column (2)
and rounded to the nearest 1,000.

... Not shown, because all calculations were based on rates for single
years of age.

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To model the incarceration experience of the adult resident population
in 2001, a separate generation life table was needed for each birth
cohort born from 1901 to 1983. For example, of those born in 1980 and
alive in 2001, an estimated 1.510% had ever gone to prison (Appendix
table 1, column 2). Multiplying by 4,140,721 U.S. residents age 21 in
2001 (column 1), produced an estimate of 63,000 persons, age 21 in
2001, who had ever been incarcerated (column 3).

Similarly, the generation life table for the 1970 birth cohort produced
an estimated prevalence of 3.584% among those age 31 in 2001.
Multiplying by 4,032,301 U.S. residents age 31 in 2001 resulted in an
estimated 145,000 persons age 31 in 2001 who had ever been
incarcerated. The estimated 5,618,000 adults ever incarcerated in 2001
was obtained by summing the number of persons ever incarcerated, age 18
or older. Dividing by the adult resident population of 210,207,901
yielded an estimated prevalence of ever having gone to prison of 2.673%
in 2001.

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+Estimating prevalence of imprisonment in the United States+

To illustrate the application of generation life table techniques
resulting in the 1.510% rate of ever having gone to prison among
persons born in 1980, consider the following calculations:

1. Estimates of the number of persons in a population of 100,000 born
in 1980 who died during each age interval were obtained by multiplying
the age-specific mortality