Year	per 1,000 people
1970	0.3
1980	0.435
1981	0.487
1984	0.534
1991	0.746
1996	0.848
2000	1.006
2002	1.151
2004	1.284
2005	1.064
2006	1.07
2007	1.038
2008	1.467
2009	1.14
2010	1.421
2011	1.514
2012	1.466
2013	1.593
2014	1.486
2015	1.754
2017	1.587
2021	1.913