Year | Value | 2022 | 50.134601421758 | 2021 | 50.133821989418 | 2020 | 50.132811143195 | 2019 | 50.129682816792 | 2018 | 50.1271356855 | 2017 | 50.126488296965 | 2016 | 50.126927126555 | 2015 | 50.12678813703 | 2014 | 50.125225078677 | 2013 | 50.122439357058 | 2012 | 50.118815214328 | 2011 | 50.113969761568 | 2010 | 50.110417290802 | 2009 | 50.104795065864 | 2008 | 50.095090638863 | 2007 | 50.086606586814 | 2006 | 50.076592681317 | 2005 | 50.064028021765 | 2004 | 50.050042728563 | 2003 | 50.035103518745 | 2002 | 50.017750310458 | 2001 | 49.998406966923 | 2000 | 49.977738831722 | 1999 | 49.955900658824 | 1998 | 49.932827445723 | 1997 | 49.908117243251 | 1996 | 49.883157465088 | 1995 | 49.858506461718 | 1994 | 49.831662506602 | 1993 | 49.803156117702 | 1992 | 49.797756458671 | 1991 | 49.841029649018 | 1990 | 49.896386619072 | 1989 | 49.946541607288 | 1988 | 50.018427584481 | 1987 | 50.056482226051 | 1986 | 50.043359133622 | 1985 | 50.030562674446 | 1984 | 50.018166060085 | 1983 | 50.006178253103 | 1982 | 49.994799896838 | 1981 | 49.983319118077 | 1980 | 49.97243825082 | 1979 | 49.96268127591 | 1978 | 49.955093483207 | 1977 | 49.94748854086 | 1976 | 49.939025501762 | 1975 | 49.931851867268 | 1974 | 49.924851356929 | 1973 | 49.916864230139 | 1972 | 49.907764239884 | 1971 | 49.898556694983 | 1970 | 49.889021082366 | 1969 | 49.879374634855 | 1968 | 49.869579495077 | 1967 | 49.859622830967 | 1966 | 49.849493017341 | 1965 | 49.839132352163 | 1964 | 49.828495503504 | 1963 | 49.817933897884 | 1962 | 49.807117641863 | 1961 | 49.795971160303 | 1960 | 49.784375552995 |
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