Year	per 1,000 people
1960	0.92567503452301
1970	1.37960004806519
1980	1.4805999994278
1981	1.51559996604919
1987	1.51049995422363
1988	1.48370003700256
1990	1.4330999851
1996	1.6000000238
2000	1.59
2001	1.59
2002	1.63
2003	1.63
2004	1.63
2005	1.72
2006	1.72
2007	1.72
2008	1.38
2009	1.38
2010	1.74
2011	1.74
2012	1.5
2013	1.5
2014	1.5
2015	1.5
2016	1.7
2017	1.56