Year years 1960 47.24 1961 48.249 1962 49.2 1963 50.078 1964 50.838 1965 51.518 1966 52.04 1967 52.769 1968 53.337 1969 53.991 1970 54.746 1971 55.386 1972 55.964 1973 56.579 1974 57.152 1975 57.583 1976 57.515 1977 57.664 1978 57.782 1979 57.856 1980 57.982 1981 58.069 1982 58.214 1983 58.72 1984 59.212 1985 59.521 1986 59.521 1987 60.047 1988 60.549 1989 61.054 1990 61.509 1991 62.004 1992 62.442 1993 62.847 1994 63.224 1995 63.214 1996 63.126 1997 63.665 1998 64.492 1999 65.189 2000 65.86 2001 67.189 2002 68.112 2003 69.344 2004 69.929 2005 70.15 2006 70.436 2007 70.796 2008 71.103 2009 71.472 2010 71.843 2011 71.694 2012 72.46 2013 72.884 2014 73.283 2015 73.684 2016 74.048 2017 74.293 2018 75.829 2019 76.645 2020 77.02 2021 75.696 2022 77.375