Year	per person
1800	0.8505
1820	0.8505
1913	1.164
1967	2.861
1968	2.905
1969	2.732
1970	2.778
1971	2.745
1972	1.897
1973	2.039
1974	2.483
1975	2.111
1976	2.32
1977	2.565
1978	2.7
1979	3.258
1980	2.956
1981	3.239
1982	3.218
1983	3.538
1984	3.463
1985	3.382
1986	3.931
1987	3.912
1988	3.941
1989	4.144
1990	4.101
1991	4.225
1992	4.627
1993	4.675
1994	4.96
1995	5.218
1996	5.154
1997	4.94
1998	4.89
1999	4.736
2000	3.952
2001	3.503
2002	3.356
2003	3.482
2004	3.666
2005	3.754
2006	3.904
2007	4.204
2008	4.388
2009	4.175