Year	per 1,000 people
1960	2.41143894195557
1970	2.17280006408691
1975	2.5
1985	1.68449997901917
1990	1.4132000208
1992	1.5
1993	1.2999999523
1994	1.3571000099
1996	1.4700000286
2003	1.3999999762
2004	0.9
2007	1.2
2008	1.5
2009	1.6
2010	1.5
2011	1.53
2012	1.52
2013	1.51
2014	1.56
2015	1.55
2016	1.59
2017	1.59