Year	per person
1800	0.7893
1820	0.7893
1913	1.22
1950	7.375
1951	7.546
1952	7.721
1953	7.892
1954	7.568
1955	8.053
1956	7.783
1957	8.395
1958	8.698
1959	8.592
1960	8.786
1961	9.789
1962	9.362
1963	9.679
1964	10.58
1965	11.19
1966	11.64
1967	12.11
1968	11.73
1969	11.86
1970	12.39
1971	12.12
1972	12
1973	12.55
1974	12
1975	7.524
1976	6.689
1977	6.598
1978	6.734
1979	6.721
1980	6.743
1981	6.477
1982	6.046
1983	5.668
1984	5.543
1985	5.467
1986	4.87
1987	5.329
1988	5.984
1989	5.988
1990	6.091
1991	5.989
1992	5.763
1993	4.101
1994	4.06
1995	4.362
1996	4.731
1997	4.994
1998	5.229
1999	5.301
2000	5.365
2001	5.438
2002	6.082
2003	6.108
2004	6.595
2005	7.748
2006	8.924
2007	10.43
2008	11.47
2009	11.09