Year per 1,000 people 1960 23.1 1961 21.3 1962 20.6 1963 22 1964 20.6 1965 20.6 1966 18.9 1967 20.4 1968 20.7 1969 19.9 1970 20 1971 16.2 1972 16.2 1973 17.7 1974 13.9 1975 12.8 1976 14.4 1977 12.6 1978 12.5 1979 14.5 1980 15.4 1981 14.4 1982 14.6 1983 13.2 1984 15.2 1985 13.9 1986 12.9 1987 13.2 1988 14.9 1989 13.2 1990 13.2 1991 14.2 1992 12.7 1993 13.8 1994 11.7 1995 13.8 1996 13.1 1997 13.9 1998 12.6 1999 12.4 2000 12.9 2001 12.1 2002 11.7 2003 10.2 2004 10.8 2005 11 2006 10.3 2007 10 2008 9.9 2009 11.4 2010 9.1 2011 10.9 2012 9.7 2013 9.2 2014 10 2015 8.7 2016 10 2017 8.9 2018 9.9 2019 9.2 2020 9.1 2021 9.6 2022 9.2