Year | Value | 2021 | 70.996258674662 | 2020 | 72.579203878751 | 2019 | 72.523409953823 | 2018 | 72.583686869614 | 2017 | 72.600894575084 | 2016 | 72.560521696091 | 2015 | 72.610263622411 | 2014 | 72.680876906199 | 2013 | 72.720908479874 | 2012 | 72.640703191961 | 2011 | 72.358461135914 | 2010 | 72.018689330378 | 2009 | 71.831907097257 | 2008 | 71.177469431063 | 2007 | 71.027971642794 | 2006 | 70.700690346094 | 2005 | 70.482335890295 | 2004 | 70.225318157492 | 2003 | 69.795845198725 | 2002 | 69.970066938785 | 2001 | 69.70136283001 | 2000 | 69.609333160745 | 1999 | 69.391280123371 | 1998 | 69.497329020685 | 1997 | 69.427210223529 | 1996 | 69.575642780443 | 1995 | 69.609269874897 | 1994 | 69.569615136294 | 1993 | 69.640250089781 | 1992 | 69.552500936865 | 1991 | 69.54915797809 | 1990 | 69.431404933709 | 1989 | 69.328643574836 | 1988 | 69.006417579946 | 1987 | 68.784050270068 | 1986 | 68.524635037908 | 1985 | 68.249144620299 | 1984 | 68.11453996694 | 1983 | 67.982749428465 | 1982 | 67.913909471584 | 1981 | 67.672228321317 | 1980 | 67.377836423878 | 1979 | 67.165850598952 | 1978 | 66.910809625417 | 1977 | 66.577220652774 | 1976 | 66.392132794191 | 1975 | 66.255983147798 | 1974 | 66.067350953283 | 1973 | 65.567031162362 | 1972 | 65.198041649476 | 1971 | 65.055342196742 | 1970 | 64.926612311071 | 1969 | 64.634454159285 | 1968 | 64.495825845385 | 1967 | 64.471591476207 | 1966 | 64.218265785098 | 1965 | 63.910156521465 | 1964 | 63.592163997326 | 1963 | 63.167160227512 | 1962 | 62.601166766596 | 1961 | 62.068665271765 | 1960 | 61.829493973711 |
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