Year years 1960 63.978 1961 64.36 1962 64.244 1963 64.449 1964 64.363 1965 64.593 1966 64.891 1967 64.992 1968 64.89 1969 64.859 1970 65.589 1971 65.541 1972 65.923 1973 66.323 1974 66.563 1975 67.081 1976 67.228 1977 67.861 1978 68.197 1979 68.491 1980 68.564 1981 68.976 1982 68.937 1983 69.267 1984 69.195 1985 69.651 1986 70.119 1987 70.564 1988 71.052 1989 71.425 1990 71.784 1991 72.319 1992 72.43 1993 72.565 1994 73.172 1995 73.133 1996 73.307 1997 73.09 1998 73.474 1999 73.722 2000 73.926 2001 74.186 2002 74.408 2003 74.08 2004 74.855 2005 75.139 2006 75.433 2007 75.006 2008 75.641 2009 75.936 2010 75.721 2011 76.124 2012 76.467 2013 76.491 2014 76.755 2015 76.76 2016 76.308 2017 76.833 2018 76.999 2019 77.284 2020 75.892 2021 75.39 2022 76.064