Year | Value | 2021 | 83.5 | 2020 | 83.2 | 2019 | 83.1 | 2018 | 82.9 | 2017 | 82.8 | 2016 | 82.6 | 2015 | 82.5 | 2014 | 82.3 | 2013 | 82.2 | 2012 | 82 | 2011 | 81.8 | 2010 | 81.4 | 2009 | 81.1 | 2008 | 80.8 | 2007 | 80.5 | 2006 | 81.5 | 2005 | 80.7 | 2004 | 81 | 2003 | 80.8 | 2002 | 80.8 | 2001 | 80.9 | 2000 | 80 | 1999 | 76.067 | 1998 | 76.197 | 1997 | 76.202 | 1996 | 76.07 | 1995 | 75.581 | 1994 | 75.56 | 1993 | 75.337 | 1992 | 75.17 | 1991 | 74.968 | 1990 | 74.717 | 1989 | 74.469 | 1988 | 74.238 | 1987 | 73.975 | 1986 | 73.501 | 1985 | 73.174 | 1984 | 72.972 | 1983 | 72.745 | 1982 | 72.554 | 1981 | 72.328 | 1980 | 72.135 | 1979 | 71.655 | 1978 | 71.466 | 1977 | 71.29 | 1976 | 71.052 | 1975 | 70.878 | 1974 | 70.699 | 1973 | 70.494 | 1972 | 69.713 | 1971 | 69.912 | 1970 | 69.254 | 1969 | 69.09 | 1968 | 68.927 | 1967 | 68.733 | 1966 | 68.224 | 1965 | 69.032 | 1964 | 67.828 | 1963 | 66.112 | 1962 | 66.489 | 1961 | 66.807 | 1960 | 67.044 |
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