Year | Value | 2022 | 50.879408553901 | 2021 | 50.932073113589 | 2020 | 50.982978513661 | 2019 | 51.022411867388 | 2018 | 51.056654799335 | 2017 | 51.08837196263 | 2016 | 51.102863283875 | 2015 | 51.086729862259 | 2014 | 51.0352822145 | 2013 | 50.948730592474 | 2012 | 50.839193011398 | 2011 | 50.720169252468 | 2010 | 50.600109286105 | 2009 | 50.483930858726 | 2008 | 50.373880140852 | 2007 | 50.267587403066 | 2006 | 50.166319031716 | 2005 | 50.074570422936 | 2004 | 49.993790178603 | 2003 | 49.925638313462 | 2002 | 49.865245182217 | 2001 | 49.808356102526 | 2000 | 49.757528860468 | 1999 | 49.710903926935 | 1998 | 49.665325433614 | 1997 | 49.622480306084 | 1996 | 49.582348702982 | 1995 | 49.543389983992 | 1994 | 49.513858218324 | 1993 | 49.493800392345 | 1992 | 49.47235807936 | 1991 | 49.45093787593 | 1990 | 49.430636767213 | 1989 | 49.410721697339 | 1988 | 49.39073408536 | 1987 | 49.370950347839 | 1986 | 49.351614149079 | 1985 | 49.332735539101 | 1984 | 49.313848889572 | 1983 | 49.294289962495 | 1982 | 49.274872243014 | 1981 | 49.257254481704 | 1980 | 49.241067018388 | 1979 | 49.224994111106 | 1978 | 49.210051464961 | 1977 | 49.194236550103 | 1976 | 49.178380927121 | 1975 | 49.162872734947 | 1974 | 49.147046948632 | 1973 | 49.131260152875 | 1972 | 49.114318266915 | 1971 | 49.095856439224 | 1970 | 49.077348658388 | 1969 | 49.059572925005 | 1968 | 49.043689887398 | 1967 | 49.030005173306 | 1966 | 49.016460698014 | 1965 | 49.001981608482 | 1964 | 48.990052423911 | 1963 | 48.978016943552 | 1962 | 48.963964135318 | 1961 | 48.950665185268 | 1960 | 48.939494292282 |
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