Year	per 1000 people
1960	0.146
1970	0.3
1980	0.435
1981	0.487
1984	0.534
1991	0.746
1996	0.848
2000	1.016
2002	1.165
2004	1.302
2005	1.078
2006	1.084
2007	1.05
2008	1.481
2009	1.15
2010	1.431
2011	1.522
2012	1.47
2015	1.746