Year	per person
1800	2.87
1820	2.931
1870	3.248
1890	4.571
1900	4.891
1910	5.731
1913	5.731
1920	5.592
1921	5.647
1922	5.73
1923	5.943
1924	6.28
1925	6.496
1926	6.851
1927	6.644
1928	7.127
1929	7.397
1930	7.15
1931	6.837
1932	6.115
1933	6.219
1934	6.362
1935	6.18
1936	6.887
1937	6.906
1938	7.356
1939	7.656
1947	7.133
1948	8.397
1949	9.101
1950	8.41
1951	8.628
1952	7.854
1953	8.908
1954	9.283
1955	9.746
1956	9.445
1957	10.92
1958	11.28
1959	12.55
1960	13.22
1961	13.67
1962	13.79
1963	15.08
1964	16.37
1965	16.65
1966	17.38
1967	17.53
1968	17.75
1969	19.57
1970	20.36
1971	22.51
1972	23.07
1973	23.65
1974	26.46
1975	26.23
1976	26.78
1977	28.47
1978	29.78
1979	31.55
1980	32.88
1981	33.26
1982	33.29
1983	33.39
1984	34.05
1985	34.14
1986	35.36
1987	34.8
1988	34.16
1989	33.58
1990	31.02
1991	28.49
1992	20.45
1993	14.21
1994	14.56
1995	15.38
1996	16.11
1997	17.36
1998	17.84
1999	13.82
2000	14.49
2001	15.22
2002	15.87
2003	16.31
2004	17.72
2005	18.88
2006	19.94
2007	21.41
2008	22.59
2009	21.94