Year years 1960 74 1961 74.2 1962 74.2 1963 74.2 1964 74.2 1965 74.2 1966 74.2 1967 74.26 1968 74.32 1969 74.38 1970 74.44 1971 74.5 1972 74.92 1973 75.34 1974 75.76 1975 76.18 1976 76.6 1977 76.94 1978 77.28 1979 77.62 1980 77.96 1981 78.3 1982 78.48 1983 78.66 1984 78.84 1985 79.02 1986 79.2 1987 79.44 1988 79.68 1989 79.92 1990 80.16 1991 80.4 1992 80.4 1993 80.9 1994 80.9 1995 80.8 1996 81.1 1997 81.4 1998 81.5 1999 81.8 2000 82 2001 82.4 2002 82.6 2003 82.8 2004 83 2005 83.3 2006 83.5 2007 83.7 2008 83.7 2009 83.9 2010 84 2011 84.2 2012 84.3 2013 84.3 2014 84.4 2015 84.5 2016 84.6 2017 84.6 2018 84.9 2019 85 2020 85.3 2021 85.4 2022 85.3