Year | Value | 2021 | 81.594946688556 | 2020 | 81.493431233436 | 2019 | 82.281962811136 | 2018 | 82.004541888923 | 2017 | 81.885477503964 | 2016 | 81.908690279818 | 2015 | 81.518753551377 | 2014 | 81.889675408046 | 2013 | 81.458973123328 | 2012 | 81.174147697875 | 2011 | 81.177846843302 | 2010 | 80.693616666309 | 2009 | 80.450687959103 | 2008 | 80.246713609617 | 2007 | 80.043336492551 | 2006 | 79.803196191422 | 2005 | 79.370626914586 | 2004 | 79.228258511419 | 2003 | 78.652034066866 | 2002 | 78.630192478069 | 2001 | 78.540004084494 | 2000 | 78.195909112471 | 1999 | 77.941979027461 | 1998 | 77.716139903276 | 1997 | 77.50532525395 | 1996 | 77.144623946599 | 1995 | 76.878439600642 | 1994 | 76.719429581758 | 1993 | 76.408835343106 | 1992 | 76.300869109701 | 1991 | 75.960149018522 | 1990 | 75.811497449535 | 1989 | 75.736628378857 | 1988 | 75.552612300515 | 1987 | 75.367189611164 | 1986 | 75.046544288052 | 1985 | 74.753781869373 | 1984 | 74.616303671913 | 1983 | 74.219700001343 | 1982 | 74.148250735091 | 1981 | 73.806945588633 | 1980 | 73.529577862592 | 1979 | 73.382613835865 | 1978 | 73.042595942899 | 1977 | 72.890703122889 | 1976 | 72.451306674674 | 1975 | 72.12515586509 | 1974 | 72.05551403824 | 1973 | 71.721991105393 | 1972 | 71.612541569139 | 1971 | 71.259987609484 | 1970 | 71.105923254452 | 1969 | 70.685254084179 | 1968 | 70.767698509065 | 1967 | 70.852197167969 | 1966 | 70.668534533074 | 1965 | 70.421248569347 | 1964 | 70.341348626184 | 1963 | 69.787421649904 | 1962 | 69.624885320746 | 1961 | 69.659185211299 | 1960 | 69.225861769168 |
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