Year	per 1,000 people
1960	26.7
1961	26
1962	25.2
1963	24.6
1964	23.4
1965	21.3
1966	19.3
1967	18.2
1968	17.6
1969	17.6
1970	17.4
1971	16.8
1972	15.9
1973	15.6
1974	15.4
1975	15.8
1976	15.6
1977	15.5
1978	15.2
1979	15.4
1980	15.4
1981	15.3
1982	15.1
1983	15
1984	15
1985	14.9
1986	14.5
1987	14.4
1988	14.5
1989	14.9
1990	15
1991	14.4
1992	14.1
1993	13.6
1994	13.3
1995	12.9
1996	12.4
1997	11.7
1998	11.4
1999	11.1
2000	10.7
2001	10.8
2002	10.5
2003	10.6
2004	10.6
2005	10.7
2006	11
2007	11.3
2008	11.5
2009	11.4
2010	11.2
2011	11
2012	11
2013	10.9
2014	10.9
2015	10.7
2016	10.6
2017	10.3
2018	10.1
2019	9.9
2020	9.5
2021	9.7
2022	9