Year years 1960 65.814 1961 66.46 1962 64.872 1963 65.839 1964 65.879 1965 65.682 1966 65.901 1967 65.855 1968 66.7 1969 66.089 1970 66.102 1971 65.685 1972 66.885 1973 66.315 1974 66.644 1975 66.923 1976 66.421 1977 67.745 1978 67.868 1979 68.702 1980 69.159 1981 68.94 1982 69.084 1983 69.306 1984 69.622 1985 70.082 1986 70.356 1987 70.88 1988 71.097 1989 71.397 1990 72.411 1991 72 1992 72.6 1993 72.2 1994 73.2 1995 73 1996 73.3 1997 74.1 1998 73.7 1999 74.6 2000 74.8 2001 74.8 2002 74.6 2003 74.8 2004 76 2005 76.7 2006 76.8 2007 76.7 2008 78.1 2009 78.1 2010 77.9 2011 78.5 2012 79.1 2013 79.8 2014 79.4 2015 80 2016 80.1 2017 79.9 2018 80.1 2019 80.2 2020 79.9 2021 80.5 2022 80.9