Year | Value | 2021 | 83.38 | 2020 | 83.5 | 2019 | 83.7 | 2018 | 83.3 | 2017 | 83.4 | 2016 | 83.5 | 2015 | 83.1 | 2014 | 83.6 | 2013 | 83 | 2012 | 83.1 | 2011 | 83.1 | 2010 | 82.6 | 2009 | 82.5 | 2008 | 82.4 | 2007 | 82.3 | 2006 | 82 | 2005 | 81.8 | 2004 | 81.6 | 2003 | 81.3 | 2002 | 81.2 | 2001 | 81.3 | 2000 | 81 | 1999 | 80.8 | 1998 | 80.6 | 1997 | 80.3 | 1996 | 79.9 | 1995 | 79.7 | 1994 | 79.6 | 1993 | 79.2 | 1992 | 79.2 | 1991 | 78.7 | 1990 | 78.419 | 1989 | 78.466 | 1988 | 78.286 | 1987 | 78.103 | 1986 | 77.638 | 1985 | 77.461 | 1984 | 77.357 | 1983 | 76.934 | 1982 | 76.645 | 1981 | 76.349 | 1980 | 76.147 | 1979 | 75.962 | 1978 | 75.633 | 1977 | 75.612 | 1976 | 74.958 | 1975 | 74.504 | 1974 | 74.593 | 1973 | 74.334 | 1972 | 74.111 | 1971 | 73.795 | 1970 | 73.547 | 1969 | 73.303 | 1968 | 73.362 | 1967 | 73.725 | 1966 | 73.458 | 1965 | 73.293 | 1964 | 73.352 | 1963 | 72.725 | 1962 | 72.583 | 1961 | 72.38 | 1960 | 71.749 |
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