Year	per person
1800	1.263
1820	1.263
1913	2.33
1970	9.263
1971	10.02
1972	10.83
1973	11.72
1974	12.69
1975	13.75
1976	14.92
1977	16.21
1978	17.6
1979	19.08
1980	20.64
1981	22.22
1982	23.85
1983	25.6
1984	27.61
1985	30
1986	32.93
1987	38.76
1988	46.61
1989	52.29
1990	53.33
1991	55.19
1992	55.09
1993	55.43
1994	56.65
1995	55.61
1996	54.75
1997	58.08
1998	61.32
1999	61.32
2000	62.96
2001	61.15
2002	58.04
2003	56.54
2004	59.15
2005	58.69
2006	58.08
2007	57.18
2008	55.59