Year	per person
1800	1.509
1820	1.509
1913	2.784
1950	4.811
1970	6.025
1971	6.409
1972	6.839
1973	7.36
1974	7.762
1975	7.902
1976	8.32
1977	8.392
1978	9.224
1979	7.413
1980	8.402
1981	9.387
1982	9.79
1983	10.11
1984	10.75
1985	10.97
1986	11.85
1987	12.87
1988	14.12
1989	14.17
1990	15
1991	15.06
1992	15.68
1993	15.63
1994	15.84
1995	16.14
1996	16.71
1997	17.13
1998	17.69
1999	17.82
2000	17.96
2001	17.31
2002	16.64
2003	17.02
2004	18.13
2005	18.81
2006	19.59
2007	19.98
2008	20.5
2009	20.44