Year	per 1,000 people
1970	21.1
1971	20.2
1972	20.5
1973	20.5
1974	19.9
1975	19.2
1976	18.3
1977	18.2
1978	17.5
1979	18.4
1980	17.1
1981	17.2
1982	16.4
1983	15.4
1984	15.4
1985	16.3
1986	17.3
1987	16.9
1988	18.6
1989	19.6
1990	19.8
1991	18.3
1992	17.1
1993	16.3
1994	14.8
1995	14.8
1996	15.6
1997	15.2
1998	14.1
1999	14
2000	15.3
2001	13.7
2002	15.1
2003	14.8
2004	14.8
2005	14.7
2006	13.8
2007	14
2008	13.8
2009	12.7
2010	13.2
2011	12
2012	12.8
2013	13
2014	13.3
2015	12.5
2016	13.8
2017	13.2
2018	13.6
2019	13.3
2020	13.1
2021	13
2022	11.8