Year years 1960 67.095 1961 67.682 1962 68.272 1963 69.222 1964 69.606 1965 70.555 1966 71.472 1967 71.515 1968 71.981 1969 71.795 1970 71.499 1971 72.568 1972 73.348 1973 73.509 1974 74.129 1975 73.999 1976 74.512 1977 74.332 1978 74.172 1979 73.346 1980 74.901 1981 74.525 1982 74.619 1983 74.82 1984 76.663 1985 77.43 1986 77.88 1987 78.542 1988 80.751 1989 79.889 1990 80.822 1991 81.516 1992 79.306 1993 79.409 1994 76.457 1995 78.225 1996 77.032 1997 77.361 1998 77.463 1999 75.969 2000 76.717 2001 77.013 2002 77.057 2003 76.841 2004 77.8 2005 76.8 2006 76.4 2007 76.9 2008 77.8 2009 77.5 2010 78.5 2011 78.8 2012 78.3 2013 79 2014 78.9 2015 78.6 2016 78.9 2017 79.2 2018 79.3 2019 79.5 2020 78.8 2021 77 2022 78.8