Year years 1960 52.793 1961 53.718 1962 54.346 1963 54.941 1964 55.775 1965 56.382 1966 56.843 1967 57.017 1968 58.273 1969 59.279 1970 59.907 1971 60.554 1972 61.11 1973 58.48 1974 62.392 1975 62.971 1976 63.238 1977 63.15 1978 64.728 1979 64.894 1980 64.836 1981 62.193 1982 57.578 1983 66.315 1984 67.412 1985 67.397 1986 67.805 1987 67.796 1988 68.119 1989 68.166 1990 68.162 1991 68.182 1992 68.512 1993 68.411 1994 68.351 1995 68.594 1996 68.516 1997 68.444 1998 68.361 1999 68.398 2000 68.652 2001 69.536 2002 69.77 2003 70.123 2004 70.406 2005 70.633 2006 70.993 2007 71.214 2008 71.113 2009 71.329 2010 71.352 2011 70.546 2012 62.428 2013 58.832 2014 58.228 2015 60.566 2016 61.574 2017 62.957 2018 65.625 2019 68.224 2020 68.888 2021 69.058 2022 68.671