Year	per 1,000 people
1970	0.513
1981	0.738
1986	1.676
1990	1.5
1996	1.26
1997	1.26
2001	2.217
2005	2.533
2006	2.279
2008	3.192
2009	3.183
2010	4.038
2014	1.927
2016	2.756
2018	2.499