Year years 1960 64.917 1961 65.325 1962 65.749 1963 66.057 1964 66.455 1965 66.674 1966 66.96 1967 67.08 1968 67.304 1969 67.351 1970 67.354 1971 67.292 1972 67.546 1973 67.603 1974 67.647 1975 67.897 1976 67.929 1977 67.958 1978 68 1979 68.296 1980 68.681 1981 69.093 1982 69.588 1983 69.317 1984 69.178 1985 69.122 1986 70.987 1987 71.331 1988 71.5 1989 72.121 1990 71.564 1991 70.302 1992 71.239 1993 70.306 1994 68.705 1995 68.961 1996 67.842 1997 68.639 1998 68.895 1999 69.044 2000 70.035 2001 70.466 2002 70.505 2003 70.997 2004 71.621 2005 72.045 2006 72.564 2007 72.996 2008 73.477 2009 73.876 2010 73.778 2011 73.679 2012 73.625 2013 73.586 2014 73.524 2015 73.838 2016 74.51 2017 75.059 2018 75.232 2019 75.617 2020 74.852 2021 73.547 2022 73.32