Year years 1960 57.376 1961 58.962 1962 58.727 1963 57.798 1964 60.249 1965 61.328 1966 63.247 1967 63.541 1968 64.301 1969 64.62 1970 65.362 1971 66.377 1972 67.286 1973 67.695 1974 68.377 1975 68.74 1976 69.612 1977 70.42 1978 71.201 1979 71.636 1980 71.363 1981 71.953 1982 71.906 1983 71.596 1984 72.237 1985 72.389 1986 72.357 1987 72.325 1988 72.796 1989 73.286 1990 73.762 1991 74.283 1992 73.761 1993 74.517 1994 74.1 1995 74 1996 74.8 1997 74.7 1998 74.5 1999 75.3 2000 75.2 2001 76.1 2002 75.6 2003 75.7 2004 75.8 2005 75.9 2006 76.2 2007 75.9 2008 76.5 2009 76.7 2010 77.2 2011 77.2 2012 76.9 2013 77.5 2014 77.5 2015 77.4 2016 77.5 2017 77.9 2018 78.8 2019 78.6 2020 76.7 2021 75.5 2022 76.74