Year	per 1,000 people
1970	15.1000003814697
1980	15.6000003814697
1985	14
1990	12.5
1991	11.1999998093
1992	11
1993	10
1994	10
1995	9.3000001907
1996	9.1999998093
1997	7.9000000954
1998	7.8000001907
1999	7.5999999046
2000	7.54
2001	7.46
2002	7.35
2003	7.24
2004	7.1
2005	7.05
2006	6.99
2007	6.73
2008	6.57
2009	6.25
2010	5.85
2011	5.52
2012	5.3
2013	4.87
2014	4.53
2015	4.35
2016	3.97
2017	3.28
2018	3.61