Year	per 1,000 people
1960	0.409490883350372
1970	0.494700014591217
1975	0.495299994945526
1987	0.543900012969971
1994	0.194600001
1995	0.1199999973
1996	0.1199999973
1997	0.1800000072
1998	0.1199999973
2005	0.3
2010	0.35
2015	0.31
2017	0.39