Year Population (in millions)
1815 8.3
1825 11.0
1835 14.7
1845 19.7
1855 26.7
1865 35.2
1875 44.4
1885 55.9
1895 68.9
1905 83.2
1915 98.8
1925 114.2
1935 127.1
1945 140.1
1955 164.0
1965 190.9
1975 214.3
This data was found on the Internet at gopher://cs.muohio.edu:70/11/Data%20Series/U.S.%20Population%20Series It contains the average population of the U.S. for decades from 1800-1810 to 1960-1970. For this analysis, I took the midpoints of the intervals as the data for the year the population is measured.