Year | Value | 2022 | 50.704991212936 | 2021 | 50.7276967149 | 2020 | 50.751909537383 | 2019 | 50.771131392683 | 2018 | 50.786017822165 | 2017 | 50.799908072201 | 2016 | 50.810255116631 | 2015 | 50.816815704837 | 2014 | 50.821203467028 | 2013 | 50.823865510134 | 2012 | 50.824780667328 | 2011 | 50.824181693356 | 2010 | 50.823634517404 | 2009 | 50.82263538118 | 2008 | 50.8195736351 | 2007 | 50.814922177817 | 2006 | 50.809352108983 | 2005 | 50.802868286223 | 2004 | 50.796010167759 | 2003 | 50.789371782605 | 2002 | 50.782560062769 | 2001 | 50.774974656001 | 2000 | 50.764035253216 | 1999 | 50.751701089457 | 1998 | 50.742978588951 | 1997 | 50.734106632932 | 1996 | 50.723025818268 | 1995 | 50.711418443214 | 1994 | 50.699578710087 | 1993 | 50.687757621128 | 1992 | 50.674535337197 | 1991 | 50.658891717682 | 1990 | 50.643212313509 | 1989 | 50.628764888857 | 1988 | 50.61681014554 | 1987 | 50.606831354249 | 1986 | 50.598444392324 | 1985 | 50.593073196609 | 1984 | 50.590287817201 | 1983 | 50.58995420674 | 1982 | 50.590034621798 | 1981 | 50.590375634254 | 1980 | 50.593176443071 | 1979 | 50.60134756884 | 1978 | 50.611356981192 | 1977 | 50.61885299592 | 1976 | 50.626796806281 | 1975 | 50.636624257374 | 1974 | 50.642737210699 | 1973 | 50.641913768526 | 1972 | 50.639164988277 | 1971 | 50.635351175097 | 1970 | 50.632313303364 | 1969 | 50.633815004845 | 1968 | 50.638757340333 | 1967 | 50.646158431983 | 1966 | 50.656066339352 | 1965 | 50.672126612907 | 1964 | 50.690568628253 | 1963 | 50.70475096725 | 1962 | 50.720271483264 | 1961 | 50.74510578186 | 1960 | 50.779586536168 |
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