Year	per 1000 people
1970	0.89
1971	0.919
1972	0.953
1973	1.012
1974	1.025
1975	1.121
1976	1.114
1977	1.158
1978	1.238
1979	1.311
1980	1.344
1981	1.466
1982	1.495
1983	1.679
1984	1.671
1985	1.809
1986	1.901
1987	1.952
1988	2.033
1989	2.14
1990	2.168
1991	2.342
1992	2.371
1993	2.343
1994	2.315
1995	2.297
1996	2.251
1997	2.249
1998	2.246
1999	2.211
2000	2.201
2001	2.191
2006	2.546
2008	2.627
2009	2.605
2010	2.687
2011	2.734
2012	2.781
2013	2.8
2015	2.875