Year years 1960 61.55 1961 62.363 1962 63.192 1963 64.101 1964 65.058 1965 66.026 1966 66.956 1967 67.859 1968 68.671 1969 69.535 1970 70.058 1971 70.683 1972 71.016 1973 71.349 1974 71.747 1975 71.977 1976 72.359 1977 72.546 1978 72.871 1979 73.035 1980 73.183 1981 73.338 1982 73.458 1983 73.471 1984 73.524 1985 73.566 1986 73.556 1987 73.554 1988 73.53 1989 73.416 1990 73.492 1991 73.435 1992 73.417 1993 73.482 1994 73.591 1995 73.636 1996 73.829 1997 73.96 1998 74.041 1999 74.347 2000 74.606 2001 75.078 2002 75.536 2003 75.478 2004 75.672 2005 75.825 2006 75.765 2007 76.131 2008 76.41 2009 76.669 2010 76.82 2011 77.104 2012 77.35 2013 77.583 2014 77.858 2015 77.913 2016 78.152 2017 78.268 2018 78.511 2019 78.691 2020 78.841 2021 78.497 2022 79.236