Year years 1960 55.931 1961 56.447 1962 56.052 1963 54.259 1964 54.918 1965 54.007 1966 53.655 1967 53.225 1968 48.21 1969 50.557 1970 50.584 1971 51.135 1972 46.984 1973 51.163 1974 49.854 1975 58.151 1976 60.558 1977 60.826 1978 61.132 1979 61.755 1980 61.982 1981 62.632 1982 62.868 1983 62.907 1984 63.063 1985 63.549 1986 63.653 1987 64.212 1988 64.195 1989 64.661 1990 64.762 1991 65.285 1992 65.358 1993 65.879 1994 65.982 1995 66.553 1996 66.696 1997 67.194 1998 67.427 1999 67.589 2000 67.773 2001 67.952 2002 68.075 2003 68.228 2004 68.348 2005 68.543 2006 68.579 2007 68.67 2008 68.613 2009 68.751 2010 68.784 2011 68.984 2012 69.007 2013 69.094 2014 69.149 2015 69.144 2016 69.18 2017 69.26 2018 69.245 2019 69.369 2020 70.787 2021 69.117 2022 69.927