Year | Value | 2022 | 50.763743642862 | 2021 | 50.740723076641 | 2020 | 50.711544236799 | 2019 | 50.691883427862 | 2018 | 50.681066146984 | 2017 | 50.671596743756 | 2016 | 50.662608799324 | 2015 | 50.653815091485 | 2014 | 50.645747432678 | 2013 | 50.637268805461 | 2012 | 50.627122630927 | 2011 | 50.61686754167 | 2010 | 50.605901541859 | 2009 | 50.592721217724 | 2008 | 50.578030660098 | 2007 | 50.565754168623 | 2006 | 50.556287658016 | 2005 | 50.546595028376 | 2004 | 50.536439688186 | 2003 | 50.525918203653 | 2002 | 50.514344480132 | 2001 | 50.502467140682 | 2000 | 50.489236111733 | 1999 | 50.475480955917 | 1998 | 50.463935008672 | 1997 | 50.452303644266 | 1996 | 50.440319149751 | 1995 | 50.428469786807 | 1994 | 50.417659512324 | 1993 | 50.405416722341 | 1992 | 50.39018265876 | 1991 | 50.374059377855 | 1990 | 50.3583546243 | 1989 | 50.343816369425 | 1988 | 50.330058938443 | 1987 | 50.316302678804 | 1986 | 50.30213511191 | 1985 | 50.288283590446 | 1984 | 50.273664578711 | 1983 | 50.257822021157 | 1982 | 50.240293392211 | 1981 | 50.22142454541 | 1980 | 50.203956124865 | 1979 | 50.186601690151 | 1978 | 50.168607152086 | 1977 | 50.15164528467 | 1976 | 50.131442302137 | 1975 | 50.10844183985 | 1974 | 50.08565278752 | 1973 | 50.062094222659 | 1972 | 50.03862160309 | 1971 | 50.013715897665 | 1970 | 49.995890672331 | 1969 | 49.986396134982 | 1968 | 49.976434327451 | 1967 | 49.966557930429 | 1966 | 49.9569481726 | 1965 | 49.946564511755 | 1964 | 49.935459619595 | 1963 | 49.924378159593 | 1962 | 49.912518421565 | 1961 | 49.898933166843 | 1960 | 49.883952767174 |
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