Year	per 1,000 people
1985	4
1986	4
1987	4
1988	4
1989	4.09999990463257
1990	4.0999999046
1991	4.0999999046
1992	4
1993	3.9000000954
1994	3.9000000954
1995	3.9000000954
1996	4
1997	3.9000000954
1998	3.9000000954
1999	3.7999999523
2000	3.71
2001	3.65
2002	3.57
2003	3.58
2004	3.59
2005	3.56
2006	3.48
2007	3.44
2008	3.39
2009	3.37
2010	3.37
2011	3.37
2012	3.41
2013	3.39
2014	3.32
2015	3.37
2016	3.39
2017	3.39
2018	3.45