U.S. Census Bureau,

U.S. Census Bureau,

Data for 1900 to 1935: http://www.census.gov/popest/archives/1990s/popclockest.txt

Data for 1940 to 1969:Current Population Reports. Population Estimates and Projections. Series p-25, No.802.

Data for 1970 to 1979: Current Population Reports. Population Estimates and Projections. Series P-25, No.917

1980 to 1989: "Monthly Estimates of the United States Population: April 1, 1980 to

July 1, 1999, with Short-Term Projections to November 1, 2000"; published January 2, 2001;

< http://www.census.gov/popest/archives/1990s/nat-total.txt >;

1990 to 1999: “National intercensal estimates (1990-2000)”; published August 13, 2004;

< http://www.census.gov/popest/archives/EST90INTERCENSAL/US-EST90INT-datasets.html >;

2000 to 2006: “Monthly Population Estimates for the United States: April 1, 2000, to May 1, 2007”;

Release Date: June 1, 2007

< http://www.census.gov/popest/national/tables/NA-EST2006-01.xls >.

For more information:

http://www.census.gov/popest/estimates.php

referenced on dataset section Notes (#2)