Year | Value | 2022 | 49.569493536328 | 2021 | 49.561311937263 | 2020 | 49.55123684756 | 2019 | 49.439689262062 | 2018 | 49.262564673622 | 2017 | 49.165973488133 | 2016 | 49.108702269733 | 2015 | 49.046440653598 | 2014 | 48.981202628597 | 2013 | 48.921908829374 | 2012 | 48.894175522483 | 2011 | 48.896883528494 | 2010 | 48.906527748187 | 2009 | 48.913008617937 | 2008 | 48.915941100957 | 2007 | 48.927678210605 | 2006 | 48.953415544292 | 2005 | 48.988126881149 | 2004 | 49.023290731216 | 2003 | 49.043331730491 | 2002 | 49.045556584335 | 2001 | 49.054049294281 | 2000 | 49.091658007515 | 1999 | 49.149235658123 | 1998 | 49.214234796239 | 1997 | 49.277514055106 | 1996 | 49.307662660452 | 1995 | 49.293868928681 | 1994 | 49.268411909779 | 1993 | 49.248770616346 | 1992 | 49.225901986745 | 1991 | 49.215489779265 | 1990 | 49.240902351777 | 1989 | 49.299873565994 | 1988 | 49.380669854843 | 1987 | 49.455212232342 | 1986 | 49.507644123984 | 1985 | 49.548090844449 | 1984 | 49.590504378004 | 1983 | 49.629094979327 | 1982 | 49.659370673075 | 1981 | 49.694775268919 | 1980 | 49.726547804248 | 1979 | 49.764632992622 | 1978 | 49.814048929469 | 1977 | 49.856582284203 | 1976 | 49.888132662705 | 1975 | 49.907250305935 | 1974 | 49.920435439324 | 1973 | 49.931323428071 | 1972 | 49.935361901456 | 1971 | 49.941458092604 | 1970 | 49.938793815006 | 1969 | 49.940782786956 | 1968 | 49.998458144426 | 1967 | 50.088874276291 | 1966 | 50.142715794775 | 1965 | 50.155364255078 | 1964 | 50.168452062959 | 1963 | 50.202438872673 | 1962 | 50.240376203942 | 1961 | 50.249443066075 | 1960 | 50.248216332261 |
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