Year | Value | 2022 | 49.921931163481 | 2021 | 49.941903493641 | 2020 | 49.959891745905 | 2019 | 49.985617858479 | 2018 | 50.018439573581 | 2017 | 50.050659424756 | 2016 | 50.083363892688 | 2015 | 50.08010389219 | 2014 | 50.033872948761 | 2013 | 49.980882557745 | 2012 | 49.925747748251 | 2011 | 49.868256740438 | 2010 | 49.848253669583 | 2009 | 49.875616455983 | 2008 | 49.911086318855 | 2007 | 49.945916269273 | 2006 | 49.980073610574 | 2005 | 50.022049685012 | 2004 | 50.074145219029 | 2003 | 50.126891738444 | 2002 | 50.177087525476 | 2001 | 50.226679009935 | 2000 | 50.252622482263 | 1999 | 50.25321985319 | 1998 | 50.253309932816 | 1997 | 50.255723195265 | 1996 | 50.25679712786 | 1995 | 50.253360520241 | 1994 | 50.246210737421 | 1993 | 50.23669647922 | 1992 | 50.230339947855 | 1991 | 50.228399440273 | 1990 | 50.205674115565 | 1989 | 50.164170494748 | 1988 | 50.126523504974 | 1987 | 50.092183154761 | 1986 | 50.058865727207 | 1985 | 50.042651818002 | 1984 | 50.050013081479 | 1983 | 50.063567084908 | 1982 | 50.081010730489 | 1981 | 50.100923256938 | 1980 | 50.132648245827 | 1979 | 50.174908960266 | 1978 | 50.21683641761 | 1977 | 50.257395445698 | 1976 | 50.297295503221 | 1975 | 50.322710159731 | 1974 | 50.318850823308 | 1973 | 50.305794511339 | 1972 | 50.297839549639 | 1971 | 50.292034434009 | 1970 | 50.300218001559 | 1969 | 50.320695825695 | 1968 | 50.342008534843 | 1967 | 50.362131112307 | 1966 | 50.38028241565 | 1965 | 50.366448502535 | 1964 | 50.31259087453 | 1963 | 50.245580921263 | 1962 | 50.173926645167 | 1961 | 50.105962871285 | 1960 | 50.067363146953 |
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