Year	per person
1800	0.8331
1820	0.8506
1913	1.896
1950	3.715
1973	5.761
1990	5.568
1991	5.052
1992	4.31
1993	3.646
1994	2.916
1995	2.73
1996	2.882
1997	3.123
1998	3.144
1999	3.215
2000	3.35
2001	3.492
2002	3.451
2003	3.638
2004	3.845
2005	3.789
2006	3.864
2007	4.147
2008	4.447
2009	4.499