Year	per person
1800	1.756
1820	1.793
1870	1.729
1890	2.433
1900	2.603
1910	3.05
1913	3.05
1920	2.976
1921	3.005
1922	3.049
1923	3.163
1924	3.342
1925	3.457
1926	3.646
1927	3.536
1928	3.793
1929	3.937
1930	3.805
1931	3.638
1932	3.254
1933	3.31
1934	3.386
1935	3.289
1936	3.665
1937	3.675
1938	3.914
1939	4.074
1947	3.796
1948	4.468
1949	4.843
1950	4.476
1951	4.592
1952	4.18
1953	4.741
1954	4.94
1955	5.187
1956	5.026
1957	5.813
1958	6.002
1959	6.677
1960	7.033
1961	7.277
1962	7.34
1963	8.026
1964	8.713
1965	8.861
1966	9.249
1967	9.327
1968	9.443
1969	10.42
1970	10.83
1971	11.98
1972	12.28
1973	12.58
1974	14.08
1975	13.96
1976	14.25
1977	15.15
1978	15.85
1979	16.79
1980	17.5
1981	17.7
1982	17.72
1983	17.77
1984	18.12
1985	18.17
1986	18.82
1987	18.52
1988	18.18
1989	17.87
1990	16.51
1991	16.44
1992	15.27
1993	14.06
1994	13.74
1995	13.52
1996	13.61
1997	13.74
1998	14.14
1999	14.69
2000	15.3
2001	14.56
2002	14.64
2003	15.02
2004	15.6
2005	16.21
2006	16.8
2007	17.73
2008	18.53
2009	18.34