Year per 1,000 people 1960 1.3 1961 1.2 1962 1.3 1963 1.3 1964 1.4 1965 1.4 1966 1.4 1967 1.5 1968 1.5 1969 1.6 1970 1.6 1971 1.7 1972 1.7 1973 1.9 1974 2 1975 2 1976 2.1 1977 2.2 1978 2.3 1979 2.3 1980 2.4 1981 2.5 1982 2.6 1983 2.8 1984 2.9 1985 2.9 1986 3.1 1987 3.3 1990 3.333 1991 3.584 1992 3.697 1993 3.798 1994 3.803 1995 3.841 1996 3.842 1997 3.957 1998 4.091 1999 4.195 2005 4.999 2006 5.366 2007 5.609 2008 5.711 2009 5.819 2010 5.803 2011 5.829 2012 5.823 2013 5.84 2014 5.883 2015 5.91 2016 6.137 2017 6.102 2018 6.161 2019 6.247 2020 6.306