Year	per 1000 people
1960	0.42
1965	0.526
1970	0.657
1975	0.667
1980	0.851
1981	0.877
1985	0.998
1986	0.723
1988	1.111
1990	1.266
1991	1.32
1992	1.348
1993	1.385
1994	1.411
1998	1.627
1999	1.393
2001	1.428
2003	1.5
2004	1.484
2005	1.501
2006	1.502
2007	1.56
2008	1.617
2009	1.676
2010	1.736
2011	1.747
2012	1.82
2013	1.913
2016	2.276