Year years 1960 60.916 1961 61.24 1962 61.035 1963 61.178 1964 61.037 1965 61.235 1966 61.525 1967 61.524 1968 61.317 1969 61.243 1970 61.971 1971 62.028 1972 62.361 1973 62.708 1974 62.803 1975 63.291 1976 63.367 1977 63.93 1978 64.38 1979 64.708 1980 64.826 1981 65.125 1982 65.083 1983 65.518 1984 65.44 1985 66.141 1986 66.655 1987 67.148 1988 67.711 1989 68.09 1990 68.552 1991 68.957 1992 69.095 1993 69.16 1994 70.18 1995 69.95 1996 70.123 1997 69.705 1998 70.149 1999 70.407 2000 70.583 2001 70.749 2002 70.752 2003 70.83 2004 71.53 2005 71.692 2006 72.066 2007 71.487 2008 72.276 2009 72.694 2010 72.516 2011 72.841 2012 72.939 2013 73.011 2014 73.424 2015 73.294 2016 72.933 2017 73.526 2018 73.631 2019 73.857 2020 72.546 2021 72.182 2022 72.851