Year | Value | 2022 | 49.503891392229 | 2021 | 49.471047717973 | 2020 | 49.438896303047 | 2019 | 49.410777217123 | 2018 | 49.386607154266 | 2017 | 49.364044119669 | 2016 | 49.342771250808 | 2015 | 49.316156316329 | 2014 | 49.280626598203 | 2013 | 49.249446793359 | 2012 | 49.224105063481 | 2011 | 49.198550315785 | 2010 | 49.185149147539 | 2009 | 49.183809761448 | 2008 | 49.182737145061 | 2007 | 49.18321660166 | 2006 | 49.196778820738 | 2005 | 49.231027282919 | 2004 | 49.279800255059 | 2003 | 49.334898827232 | 2002 | 49.353089038403 | 2001 | 49.326604419408 | 2000 | 49.293108762653 | 1999 | 49.258615912323 | 1998 | 49.224216079246 | 1997 | 49.189316294725 | 1996 | 49.153597843112 | 1995 | 49.122090341628 | 1994 | 49.093675566175 | 1993 | 49.075235505794 | 1992 | 49.055671277863 | 1991 | 49.020153736924 | 1990 | 48.969652072641 | 1989 | 48.915638246407 | 1988 | 48.853478059931 | 1987 | 48.768039881689 | 1986 | 48.673918268791 | 1985 | 48.586104731165 | 1984 | 48.507315684648 | 1983 | 48.408709860133 | 1982 | 48.284845916579 | 1981 | 48.361141450576 | 1980 | 48.488837056391 | 1979 | 48.451258436598 | 1978 | 48.434175673322 | 1977 | 48.42918140546 | 1976 | 48.422841955896 | 1975 | 48.433023781616 | 1974 | 48.448600985956 | 1973 | 48.44686080885 | 1972 | 48.448430493869 | 1971 | 48.452152346261 | 1970 | 48.453978696791 | 1969 | 48.455887845633 | 1968 | 48.462406115474 | 1967 | 48.478191135224 | 1966 | 48.501029580254 | 1965 | 48.528537651843 | 1964 | 48.558848307945 | 1963 | 48.587864170462 | 1962 | 48.618751119772 | 1961 | 48.652087449466 | 1960 | 48.685667633808 |
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