Year years 1960 49.371 1961 49.97 1962 50.244 1963 51.103 1964 51.625 1965 52.06 1966 52.577 1967 53.062 1968 53.536 1969 53.987 1970 46.816 1971 54.762 1972 55.25 1973 55.531 1974 55.858 1975 56.209 1976 56.512 1977 56.802 1978 57.088 1979 57.336 1980 57.521 1981 57.661 1982 57.658 1983 57.553 1984 57.608 1985 58.578 1986 59.303 1987 60.069 1988 60.863 1989 61.577 1990 62.428 1991 62.843 1992 63.539 1993 64.151 1994 64.775 1995 65.176 1996 65.684 1997 66.138 1998 66.623 1999 67.298 2000 68.03 2001 68.758 2002 69.496 2003 70.16 2004 70.689 2005 71.053 2006 71.243 2007 71.272 2008 71.383 2009 71.398 2010 71.623 2011 72.086 2012 72.513 2013 72.948 2014 73.321 2015 73.577 2016 73.697 2017 73.729 2018 73.8 2019 73.904 2020 70.808 2021 70.121 2022 71.332