Year | Value | 2022 | 49.774286453951 | 2021 | 49.819653009454 | 2020 | 49.855616779093 | 2019 | 49.881142959948 | 2018 | 49.913005398213 | 2017 | 49.958557353389 | 2016 | 50.005245479858 | 2015 | 50.044398105912 | 2014 | 50.076358389417 | 2013 | 50.111446643036 | 2012 | 50.148447172695 | 2011 | 50.187993755275 | 2010 | 50.229453559918 | 2009 | 50.269728715691 | 2008 | 50.309773793961 | 2007 | 50.35230875885 | 2006 | 50.397396283305 | 2005 | 50.445546472434 | 2004 | 50.496697821267 | 2003 | 50.493469371551 | 2002 | 50.428917860011 | 2001 | 50.356795528874 | 2000 | 50.281003260974 | 1999 | 50.2029936785 | 1998 | 50.12116972641 | 1997 | 50.034114470055 | 1996 | 49.9416448492 | 1995 | 49.839582038712 | 1994 | 49.788769376483 | 1993 | 49.796034329683 | 1992 | 49.804658169674 | 1991 | 49.814294402869 | 1990 | 49.82362461115 | 1989 | 49.83372514448 | 1988 | 49.847192140031 | 1987 | 49.865068146256 | 1986 | 49.88505805715 | 1985 | 49.902239578894 | 1984 | 49.917018846523 | 1983 | 49.933976263083 | 1982 | 49.95335128602 | 1981 | 49.975655764529 | 1980 | 50.001866109322 | 1979 | 50.063599408525 | 1978 | 50.152532830564 | 1977 | 50.237163370571 | 1976 | 50.321531429922 | 1975 | 50.404577991875 | 1974 | 50.488062678857 | 1973 | 50.57515056859 | 1972 | 50.666743809886 | 1971 | 50.68949508451 | 1970 | 50.637769202828 | 1969 | 50.581309946738 | 1968 | 50.52550440546 | 1967 | 50.473488155521 | 1966 | 50.429033365247 | 1965 | 50.39103744055 | 1964 | 50.35289795287 | 1963 | 50.289644942739 | 1962 | 50.199277813043 | 1961 | 50.148757595271 | 1960 | 50.144189928315 |
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