Year years 1960 56.82 1961 57.15 1962 57.663 1963 58.212 1964 58.719 1965 59.184 1966 59.388 1967 59.705 1968 59.771 1969 59.99 1970 60.028 1971 59.935 1972 59.998 1973 60.37 1974 60.434 1975 60.473 1976 60.74 1977 60.746 1978 60.754 1979 61.03 1980 61.377 1981 61.84 1982 62.464 1983 61.791 1984 61.92 1985 61.997 1986 63.964 1987 64.584 1988 64.51 1989 64.915 1990 64.302 1991 63.424 1992 62.572 1993 62.628 1994 61.33 1995 61.17 1996 60.578 1997 61.604 1998 62.011 1999 61.996 2000 62.719 2001 63.035 2002 63.289 2003 63.754 2004 64.03 2005 64.229 2006 64.367 2007 64.853 2008 65.265 2009 65.275 2010 64.993 2011 64.805 2012 64.781 2013 64.75 2014 64.695 2015 64.827 2016 65.474 2017 66.077 2018 65.921 2019 66.378 2020 65.692 2021 64.443 2022 64.217