Year | Value | 2022 | 50.738718347823 | 2021 | 50.751102371277 | 2020 | 50.740592992866 | 2019 | 50.751309378277 | 2018 | 50.776266344604 | 2017 | 50.801652786621 | 2016 | 50.827553995971 | 2015 | 50.854491885914 | 2014 | 50.880321363651 | 2013 | 50.891916269947 | 2012 | 50.895461116452 | 2011 | 50.908279893476 | 2010 | 50.936405641454 | 2009 | 50.976413206915 | 2008 | 51.017012630722 | 2007 | 51.056155020556 | 2006 | 51.095347175083 | 2005 | 51.13623751023 | 2004 | 51.17459810687 | 2003 | 51.211744140683 | 2002 | 51.24984250115 | 2001 | 51.28760944475 | 2000 | 51.313872107759 | 1999 | 51.329510641227 | 1998 | 51.345291763808 | 1997 | 51.359737345224 | 1996 | 51.373953915105 | 1995 | 51.389537827994 | 1994 | 51.407748751078 | 1993 | 51.428735343906 | 1992 | 51.445646747014 | 1991 | 51.459018910527 | 1990 | 51.464597495125 | 1989 | 51.465835883676 | 1988 | 51.471998860265 | 1987 | 51.478856409801 | 1986 | 51.488787383477 | 1985 | 51.497370593786 | 1984 | 51.504667847606 | 1983 | 51.515231258698 | 1982 | 51.524657190506 | 1981 | 51.532040333203 | 1980 | 51.54203578168 | 1979 | 51.55262521405 | 1978 | 51.561882256062 | 1977 | 51.569752237148 | 1976 | 51.574507406986 | 1975 | 51.577398719194 | 1974 | 51.583432078124 | 1973 | 51.588685625503 | 1972 | 51.588246191483 | 1971 | 51.580713344374 | 1970 | 51.568395417438 | 1969 | 51.554511293567 | 1968 | 51.540173748495 | 1967 | 51.529916473401 | 1966 | 51.522435971539 | 1965 | 51.519201296955 | 1964 | 51.520722079019 | 1963 | 51.520791809254 | 1962 | 51.516608212577 | 1961 | 51.510965314425 | 1960 | 51.494932260669 |
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