Year	per person
1800	1.701
1820	1.701
1913	3.138
1970	12.48
1971	12.01
1972	13.23
1973	13.63
1974	13.48
1975	13.86
1976	14.02
1977	14.02
1978	15.04
1979	16.46
1980	17.25
1981	17.88
1982	17.65
1983	17.58
1984	18.12
1985	19.68
1986	21.73
1987	23.26
1988	25.45
1989	26.8
1990	27.05
1991	25.68
1992	26.75
1993	28.01
1994	29.56
1995	28.26
1996	28.42
1997	30.91
1998	33.55
1999	34.24
2000	34.1
2001	34.38
2002	33.29
2003	33.55
2004	40.09
2005	42.72
2006	50.36
2007	59.15
2008	66.62