| Year | Value | | 2021 | 85.492682926829 | | 2020 | 85.49756097561 | | 2019 | 85.180487804878 | | 2018 | 84.934146341463 | | 2017 | 84.680487804878 | | 2016 | 84.226829268293 | | 2015 | 84.278048780488 | | 2014 | 83.980487804878 | | 2013 | 83.831707317073 | | 2012 | 83.480487804878 | | 2011 | 83.421951219512 | | 2010 | 82.978048780488 | | 2009 | 82.775609756098 | | 2008 | 82.375609756098 | | 2007 | 82.326829268293 | | 2006 | 82.375609756098 | | 2005 | 81.629268292683 | | 2004 | 81.829268292683 | | 2003 | 81.378048780488 | | 2002 | 81.426829268293 | | 2001 | 81.424390243902 | | 2000 | 80.878048780488 | | 1999 | 80.382926829268 | | 1998 | 80.131707317073 | | 1997 | 80.126829268293 | | 1996 | 79.626829268293 | | 1995 | 78.682926829268 | | 1994 | 78.529268292683 | | 1993 | 78.031707317073 | | 1992 | 77.678048780488 | | 1991 | 77.882926829268 | | 1990 | 77.380487804878 | | 1989 | 77.029268292683 | | 1988 | 77.082926829268 | | 1987 | 76.882926829268 | | 1986 | 76.685365853658 | | 1985 | 76.434146341463 | | 1984 | 76.029268292683 | | 1983 | 75.275609756098 | | 1982 | 75.429268292683 | | 1981 | 75.324390243902 | | 1980 | 74.673170731707 | | 1979 | 73.673170731707 | | 1978 | 73.575609756098 | | 1977 | 73.319512195122 | | 1976 | 72.819512195122 | | 1975 | 73.368292682927 | | 1974 | 72.612195121951 | | 1973 | 72.109756097561 | | 1972 | 71.456097560976 | | 1971 | 71.458536585366 | | 1970 | 71.049951219512 | | 1969 | 70.56856097561 | | 1968 | 70.355829268293 | | 1967 | 69.92543902439 | | 1966 | 69.538878048781 | | 1965 | 69.251219512195 | | 1964 | 68.446097560976 | | 1963 | 67.685731707317 | | 1962 | 66.977170731707 | | 1961 | 66.55887804878 | | 1960 | 65.866292682927 |
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