http://www.npg.org/facts/us_historical_pops.htm
On July 1 of U.S. Population[1]
1900 76094000
1901 77584000
1902 79163000
1903 80632000
1904 82166000
1905 83822000
1906 85450000
1907 87008000
1908 88710000
1909 90490000
1910 92407000
1911 93863000
1912 95335000
1913 97225000
1914 99111000
1915 100546000
1916 101961000
1917 103268000
1918 103208000
1919 104514000
1920 106461000
1921 108538000
1922 110049000
1923 111947000
1924 114109000
1925 115829000
1926 117397000
1927 119035000
1928 120509000
1929 121767000
1930 123076741
1931 124039648
1932 124840471
1933 125578763
1934 126373773
1935 127250232
1936 128053180
1937 128824829
1938 129824939
1939 130879718
1940 132122446
1941 133402471
1942 134859553
1943 136739353
1944 138397345
1945 139928165
1946 141388566
1947 144126071
1948 146631302
1949 149188130
1950 152271417
1951 154877889
1952 157552740
1953 160184192
1954 163025854
1955 165931202
1956 168903031
1957 171984130
1958 174881904
1959 177829628
1960 180671158
1961 183691481
1962 186537737
1963 189241798
1964 191888791
1965 194302963
1966 196560338
1967 198712056
1968 200706052
1969 202676946
1970 205052174
1971 207660677
1972 209896021
1973 211908788
1974 213853928
1975 215973199
1976 218035164
1977 220239425
1978 222584545
1979 225055487
1980 227224681
1981 229465714
1982 231664458
1983 233791994
1984 235824902
1985 237923795
1986 240132887
1987 242288918
1988 244498982
1989 246819230
1990 249464396
1991 252153092
1992 255029699
1993 257782608
1994 260327021
1995 262803276
1996 265228572
1997 267783607
1998 270248003
1999 272690813
2000 282406930
2001 285339493
2002 288188925
2003 290940860
2004 293608957
2005 296328962
2006 299157432
2007 302045179

[1]
Source: U.S. Bureau of the Census,  Current Population Reports, Series P-25, Nos. 311, 917, 1095 released on June 4, 1999