Year	per person
1800	0.8874
1820	0.8874
1913	1.2
1970	5.234
1971	4.638
1972	4.144
1973	4.142
1974	4.171
1975	4.2
1976	4.27
1977	4.386
1978	4.408
1979	5.834
1980	7.756
1981	11.02
1982	14.39
1983	14.25
1984	15.88
1985	16.7
1986	17.37
1987	17.15
1988	17.52
1989	18.35
1990	19.79
1991	21.09
1992	22.18
1993	22.89
1994	23.73
1995	22.81
1996	23.07
1997	23.02
1998	23.48
1999	24.84
2000	29.14
2001	31.45
2002	33.15
2003	36.82
2004	39.42
2005	40.53
2006	40.28
2007	40.39
2008	41.24