Year	per person
1800	2.232
1820	2.232
1913	4.118
1950	7.116
1960	11.67
1961	12.53
1962	13.61
1963	12.86
1964	13.44
1965	14.93
1966	15.48
1967	17.08
1968	18.22
1969	19.53
1970	21.3
1971	21.52
1972	21.61
1973	21.91
1974	24.71
1975	24.09
1976	25.03
1977	25.92
1978	27.14
1979	29.17
1980	30.39
1981	29.62
1982	27.93
1983	27.81
1984	28.52
1985	28.55
1986	29.74
1987	30.23
1988	31.01
1989	31.86
1990	30.6
1991	29.15
1992	26.89
1993	26.97
1994	27.93
1995	28.53
1996	29.29
1997	30.49
1998	32.24
1999	32.26
2000	32.86
2001	31.87
2002	31.9
2003	32.41
2004	33.48
2005	34.73
2006	35.73
2007	36.85
2008	36.81
2009	34.75