Year years 1960 64.78 1961 64.884 1962 64.965 1963 65.035 1964 65.109 1965 65.2 1966 65.307 1967 65.41 1968 65.52 1969 65.601 1970 65.65 1971 65.672 1972 65.52 1973 65.704 1974 65.757 1975 65.86 1976 66.015 1977 66.212 1978 66.442 1979 66.702 1980 66.986 1981 67.285 1982 67.585 1983 67.874 1984 68.147 1985 68.397 1986 68.623 1987 68.822 1988 68.991 1989 69.131 1990 69.242 1991 69.33 1992 69.405 1993 69.479 1994 69.561 1995 69.661 1996 69.787 1997 69.938 1998 70.118 1999 70.329 2000 70.575 2001 70.85 2002 71.135 2003 71.419 2004 71.683 2005 71.91 2006 72.109 2007 72.271 2008 72.412 2009 72.534 2010 72.649 2011 72.764 2012 72.888 2013 73.029 2014 73.196 2015 73.392 2016 73.586 2017 73.732 2018 73.753 2019 73.579 2020 74.688 2021 71.654 2022 74.147