Year years 1960 54.688 1961 55.315 1962 55.89 1963 56.46 1964 53.601 1965 57.54 1966 57.922 1967 58.553 1968 59.076 1969 59.64 1970 60.18 1971 60.704 1972 61.23 1973 61.747 1974 62.25 1975 62.764 1976 63.214 1977 63.642 1978 63.999 1979 64.39 1980 64.748 1981 65.095 1982 65.419 1983 65.736 1984 66.048 1985 66.347 1986 66.623 1987 66.883 1988 67.188 1989 67.471 1990 67.658 1991 67.881 1992 68.385 1993 68.701 1994 68.98 1995 69.298 1996 69.588 1997 69.875 1998 70.171 1999 70.456 2000 70.746 2001 71.019 2002 71.276 2003 71.496 2004 71.696 2005 71.754 2006 72.021 2007 72.1 2008 72.155 2009 70.066 2010 72.249 2011 72.26 2012 72.167 2013 72.391 2014 72.463 2015 72.515 2016 72.54 2017 72.59 2018 72.636 2019 72.157 2020 72.768 2021 72.767 2022 72.598