Year	per 1,000 people
1960	0.91
1965	1.378
1970	1.729
1990	2.538
1991	2.695
1992	2.618
1998	2.433
1999	2.54
2002	2.699
2008	2.879
2009	2.678
2010	2.774
2011	2.895
2012	3.079
2013	3.132
2014	3.204
2015	3.256
2016	2.885
2018	3.859