Year years 1960 47.236 1961 48.064 1962 48.718 1963 49.518 1964 50.513 1965 51.735 1966 53.097 1967 54.407 1968 55.678 1969 56.675 1970 57.368 1971 57.739 1972 49.888 1973 58.095 1974 58.211 1975 58.434 1976 58.785 1977 59.215 1978 58.467 1979 58.648 1980 60.817 1981 61.276 1982 61.685 1983 61.96 1984 62.332 1985 62.87 1986 63.568 1987 64.142 1988 64.954 1989 65.852 1990 66.45 1991 67.014 1992 67.346 1993 67.774 1994 68.271 1995 68.614 1996 69.046 1997 69.505 1998 67.709 1999 70.081 2000 70.189 2001 70.163 2002 70.137 2003 70.179 2004 70.4 2005 70.937 2006 71.753 2007 72.591 2008 73.674 2009 74.545 2010 75.128 2011 75.528 2012 75.707 2013 75.763 2014 75.822 2015 75.925 2016 76.122 2017 76.367 2018 76.681 2019 77.001 2020 75.012 2021 76.803 2022 77.556