Year years 1960 43.555 1961 44.274 1962 45.072 1963 45.88 1964 46.658 1965 47.33 1966 47.608 1967 47.438 1968 47.939 1969 47.679 1970 47.897 1971 48.361 1972 48.743 1973 48.54 1974 49.752 1975 50.437 1976 51.157 1977 51.953 1978 52.864 1979 53.698 1980 54.586 1981 55.273 1982 55.995 1983 56.885 1984 57.83 1985 58.63 1986 59.358 1987 60.27 1988 60.984 1989 61.831 1990 62.227 1991 62.912 1992 63.228 1993 63.714 1994 63.876 1995 64.263 1996 64.68 1997 65.104 1998 65.528 1999 65.81 2000 65.897 2001 66.168 2002 66.383 2003 66.159 2004 66.336 2005 66.38 2006 66.525 2007 66.623 2008 66.785 2009 66.951 2010 67.096 2011 67.253 2012 67.513 2013 67.398 2014 67.773 2015 67.967 2016 68.233 2017 68.712 2018 68.875 2019 69.049 2020 68.667 2021 67.935 2022 67.869