Year	per 1000 people
1960	0.21
1965	0.205
1970	0.205
1975	0.204
1980	0.371
1981	0.27
1984	0.396
1988	0.407
1991	1.225
1992	0.48
1993	0.407
1998	0.513
2000	0.527
2001	0.538
2002	0.557
2003	0.564
2004	0.573
2005	0.577
2006	0.587
2007	0.6
2008	0.615
2009	0.624
2010	0.663
2011	0.739
2012	0.699
2014	0.725
2016	0.758