Year	per 1,000 people
1960	0.222
1970	0.346
1984	0.49
1988	0.553
1990	0.5
1993	0.578
1995	0.65
1997	0.389
1999	0.552
2000	0.54
2001	0.538
2002	0.536
2003	0.534
2006	0.622
2017	1.29
2018	1.314