Year per 1,000 people 1960 37.5 1961 35.2 1962 33.7 1963 33.2 1964 31.6 1965 29.5 1966 28.3 1967 25.6 1968 23.5 1969 21.8 1970 22.1 1971 22.3 1972 23.1 1973 22 1974 19.4 1975 17.7 1976 18.7 1977 16.5 1978 16.8 1979 17.1 1980 17.6 1981 17.6 1982 17.5 1983 16.3 1984 16.5 1985 16.6 1986 14.8 1987 16.6 1988 19.8 1989 17.5 1990 18.2 1991 17.1 1992 16.8 1993 16.8 1994 16.2 1995 15.6 1996 15.2 1997 14.5 1998 13.1 1999 12.8 2000 13.7 2001 11.8 2002 11.4 2003 10.5 2004 10.3 2005 10.2 2006 10.3 2007 10.3 2008 10.2 2009 9.9 2010 9.3 2011 9.5 2012 10.1 2013 9.3 2014 9.8 2015 9.7 2016 9.4 2017 8.9 2018 8.8 2019 8.8 2020 8.5 2021 8.6 2022 7.9