Year | Value | 2022 | 49.602342792824 | 2021 | 49.595349907752 | 2020 | 49.588415660903 | 2019 | 49.581540790119 | 2018 | 49.576903946316 | 2017 | 49.573465932791 | 2016 | 49.567988219457 | 2015 | 49.562388884494 | 2014 | 49.571946545549 | 2013 | 49.597590695107 | 2012 | 49.626144776543 | 2011 | 49.654857054511 | 2010 | 49.681311594457 | 2009 | 49.707235875845 | 2008 | 49.734340461754 | 2007 | 49.760748760045 | 2006 | 49.786978863359 | 2005 | 49.810882338368 | 2004 | 49.815495979919 | 2003 | 49.807200304444 | 2002 | 49.803865467283 | 2001 | 49.80342253674 | 2000 | 49.807129745548 | 1999 | 49.813354017261 | 1998 | 49.818846173052 | 1997 | 49.823610659702 | 1996 | 49.835088385726 | 1995 | 49.854122796621 | 1994 | 49.874915504529 | 1993 | 49.897039589388 | 1992 | 49.920501737956 | 1991 | 49.946306531672 | 1990 | 49.973403287516 | 1989 | 50.001073081116 | 1988 | 50.03159539441 | 1987 | 50.066330832889 | 1986 | 50.104537222059 | 1985 | 50.144991292504 | 1984 | 50.187227537915 | 1983 | 50.231625901806 | 1982 | 50.278122738832 | 1981 | 50.323776999834 | 1980 | 50.367624871911 | 1979 | 50.408603148097 | 1978 | 50.443604278866 | 1977 | 50.476654823079 | 1976 | 50.511764746093 | 1975 | 50.54983536472 | 1974 | 50.591811955823 | 1973 | 50.621168413111 | 1972 | 50.635048374634 | 1971 | 50.645776383827 | 1970 | 50.653108474879 | 1969 | 50.658528676614 | 1968 | 50.660742355169 | 1967 | 50.660593187521 | 1966 | 50.658210057987 | 1965 | 50.652081820382 | 1964 | 50.643535426377 | 1963 | 50.633133015341 | 1962 | 50.637441680939 | 1961 | 50.647562733144 | 1960 | 50.647010268868 |
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