Year	per person
1800	0.8933
1820	0.8933
1913	1.38
1950	1.81
1951	1.844
1952	1.867
1953	1.899
1954	1.931
1955	1.96
1956	1.987
1957	2.014
1958	2.037
1959	2.07
1960	2.09
1961	2.13
1962	2.157
1963	2.192
1964	2.234
1965	2.268
1966	2.454
1967	2.664
1968	2.893
1969	3.123
1970	3.361
1971	3.88
1972	4.964
1973	5.83
1974	6.749
1975	6.353
1976	7.174
1977	7.05
1978	7.983
1979	8.374
1980	9.163
1981	9.647
1982	9.981
1983	11.14
1984	11.95
1985	12.4
1986	12.92
1987	13.61
1988	15.26
1989	16.71
1990	17.17
1991	17.47
1992	17.44
1993	17.24
1994	17.32
1995	17.61
1996	18.16
1997	18.96
1998	19.72
1999	20.65
2000	22.17
2001	23.12
2002	24.13
2003	24.98
2004	25.71
2005	26.44
2006	27.57
2007	28.53
2008	29.04
2009	26.93