Year	per 1,000 people
1960	2.6310875415802
1970	2.17109990119934
1975	2.00270009040833
1986	1.72119998931885
1989	0.877799987792969
1990	1.1000000238
1993	1.1000000238
1996	0.9800000191
2002	0.5
2005	0.7
2007	0.7
2008	0.6
2009	0.6
2010	0.6
2011	0.66
2012	0.61
2014	0.62
2015	0.58
2017	0.44