Year	per person
1800	2.168
1820	2.214
1913	4.935
1950	9.671
1973	25.27
1990	28.83
1991	27.14
1992	21.37
1993	17.96
1994	16.24
1995	17.11
1996	17.94
1997	19.22
1998	20.64
1999	20.31
2000	21.12
2001	22.53
2002	24.14
2003	26.58
2004	28.62
2005	30.89
2006	33.51
2007	37.01
2008	38.23
2009	32.74