Year years 1960 61.2 1961 61.6 1962 62 1963 62.5 1964 63 1965 63.5 1966 64 1967 64.5 1968 65 1969 65.5 1970 66 1971 66.5 1972 67 1973 67.5 1974 68 1975 68.5 1976 69 1977 69.5 1978 69.825 1979 70.15 1980 70.475 1981 70.8 1982 70.3 1983 71.2 1984 71.7 1985 72.3 1986 72.7 1987 72.5 1988 73.5 1989 71.8 1990 73.2 1991 74.2 1992 75.2 1993 75.6 1994 73.9 1995 75.8 1996 74.2 1997 74.3 1998 77.5 1999 77 2000 78.8 2001 77.7 2002 79.2 2003 78.6 2004 78.8 2005 79 2006 79.2 2007 79.5 2008 79.6 2009 79.9 2010 80.2 2011 79.5 2012 80.1 2013 80.2 2014 79.9 2015 80.2 2016 79.8 2017 80.1 2018 83.821 2019 84.212 2020 84.596 2021 83.082 2022 84.612