Year	per 1,000 people
1960	0.152
1965	0.259
1970	0.368
1980	1.333
1981	1.633
1982	1.562
1983	1.44
1990	1.071
1993	1.441
1997	1.3
2004	1.243
2008	1.792
2009	1.888
2014	2.148
2015	1.963
2017	2.157