Year years 1960 69.903 1961 68.597 1962 70.3 1963 69.491 1964 70.413 1965 70.457 1966 70.146 1967 70.531 1968 71.805 1969 71.131 1970 71.688 1971 71.384 1972 73.165 1973 72.581 1974 73.02 1975 73.143 1976 72.967 1977 73.512 1978 73.637 1979 74.025 1980 74.475 1981 74.206 1982 72.182 1983 73.847 1984 74.623 1985 75.891 1986 75.672 1987 76.575 1988 76.702 1989 77.483 1990 78.38 1991 77.667 1992 77.435 1993 79.357 1994 78.354 1995 79.8 1996 79.8 1997 80.3 1998 80.2 1999 79.6 2000 80.5 2001 81.2 2002 81.3 2003 80.8 2004 81.2 2005 81.4 2006 82 2007 82.2 2008 82.3 2009 82.7 2010 83.6 2011 83 2012 83 2013 84 2014 84.3 2015 84.1 2016 84.4 2017 84.6 2018 84.6 2019 84.6 2020 84.5 2021 84.3 2022 84.8