Year	per 1,000 people
1960	6.22222232818604
1970	7.2536997795105
1980	5.771399974823
1990	8
1993	8.1778001785
1995	5.5
1996	5.2699999809
2000	6.2
2002	6.9
2003	5.6999998093
2005	4.1
2007	2.6
2008	2.6
2009	2.4
2011	3.6
2012	3.58
2013	3.81
2014	3.8
2015	3.78
2016	3.58
2017	3.57