Year years 1960 58.237 1961 59.211 1962 60.083 1963 60.948 1964 61.849 1965 62.535 1966 62.208 1967 61.343 1968 61.51 1969 62.732 1970 64.114 1971 64.119 1972 63.99 1973 64.177 1974 65.371 1975 66.165 1976 67.034 1977 67.769 1978 68.671 1979 69.383 1980 69.66 1981 70.078 1982 70.405 1983 70.703 1984 70.834 1985 71.013 1986 71.318 1987 71.668 1988 72.174 1989 72.835 1990 73.4 1991 73.9 1992 73.9 1993 74 1994 74 1995 74.28 1996 74.4 1997 74.4 1998 74.5 1999 74.7 2000 75.3 2001 75.3 2002 75.5 2003 75.6 2004 75.8 2005 75.91 2006 75.91 2007 76.11 2008 76.11 2009 76.56 2010 76.65 2011 76.97 2012 77.5 2013 77.5 2014 77.58 2015 77.79 2016 77.76 2017 77.89 2018 77.72 2019 77.56 2020 77.66 2021 77.24 2022 77.1