Year	per 1,000 people
1960	0.244
1965	0.257
1970	0.306
1981	0.338
1986	0.347
1987	0.376
1988	0.318
1993	0.318
1996	0.85
1998	1.049
2004	0.88
2005	0.882
2006	0.531
2014	1.457
2015	1.106
2017	1.078
2018	1.514