Year	per person
1800	1.361
1820	1.361
1913	2.511
1970	12.83
1971	13.12
1972	13.33
1973	13.61
1974	14.1
1975	14.74
1976	14.49
1977	14.24
1978	15.07
1979	16.82
1980	18.57
1981	19.24
1982	20.23
1983	19.88
1984	20.48
1985	21.96
1986	22.9
1987	24.14
1988	26.85
1989	29.22
1990	33.56
1991	26.47
1992	26.94
1993	27.51
1994	28.21
1995	27.28
1996	23.48
1997	21.53
1998	23.05
1999	25.11
2000	27.95
2001	27.84
2002	29.34
2003	26.71
2004	26.59
2005	25.39
2006	23.28
2007	23.61
2008	26.26