Year	per person
1800	1.126
1820	1.149
1913	2.562
1950	5.021
1973	14.98
1990	11.25
1991	10.46
1992	8.688
1993	8.627
1994	6.984
1995	6.35
1996	6.642
1997	5.77
1998	6.062
1999	6.929
2000	7.214
2001	7.371
2002	7.367
2003	7.725
2004	8.701
2005	9.314
2006	10.21
2007	11.22
2008	12.2
2009	12.51