Year years 1960 44.994 1961 45.811 1962 46.411 1963 47.072 1964 47.813 1965 48.65 1966 49.551 1967 50.415 1968 51.301 1969 52.032 1970 52.593 1971 52.96 1972 47.339 1973 53.4 1974 53.531 1975 53.68 1976 53.863 1977 53.392 1978 49.239 1979 44.569 1980 55.074 1981 55.204 1982 55.605 1983 52.144 1984 50.727 1985 50.946 1986 52.582 1987 51.955 1988 55.914 1989 59.128 1990 59.766 1991 60.834 1992 61.173 1993 61.584 1994 62.079 1995 62.579 1996 63.032 1997 63.504 1998 62.661 1999 64.153 2000 64.282 2001 64.284 2002 64.256 2003 64.3 2004 64.498 2005 64.985 2006 65.73 2007 66.54 2008 67.492 2009 68.296 2010 68.854 2011 69.263 2012 69.484 2013 69.612 2014 69.77 2015 70.005 2016 70.344 2017 70.686 2018 70.964 2019 71.066 2020 68.648 2021 70.836 2022 71.613