Year years 1960 52.828 1961 53.961 1962 55.023 1963 55.882 1964 56.56 1965 56.742 1966 56.238 1967 55.442 1968 55.959 1969 57.115 1970 58.035 1971 58.008 1972 57.632 1973 58.085 1974 58.094 1975 58.728 1976 58.898 1977 59.946 1978 60.711 1979 61.424 1980 62.156 1981 63.186 1982 63.825 1983 64.031 1984 64.02 1985 64.136 1986 64.393 1987 64.696 1988 64.73 1989 65.25 1990 65.6 1991 66.2 1992 66.4 1993 66.4 1994 66.5 1995 66.56 1996 66.44 1997 66.6 1998 66.9 1999 67.4 2000 68.2 2001 68.4 2002 68.6 2003 68.8 2004 68.9 2005 69.12 2006 69.12 2007 69.2 2008 69.2 2009 69.38 2010 69.46 2011 69.74 2012 70.4 2013 70.7 2014 70.97 2015 71.08 2016 71.19 2017 71.3 2018 71.27 2019 71.07 2020 70.86 2021 70.29 2022 70.1