Year | Value | 2022 | 49.826567704075 | 2021 | 49.800627972289 | 2020 | 49.778861240773 | 2019 | 49.763844738137 | 2018 | 49.750718883161 | 2017 | 49.738364390368 | 2016 | 49.725665291389 | 2015 | 49.713108717293 | 2014 | 49.701209429885 | 2013 | 49.68975891377 | 2012 | 49.678052282148 | 2011 | 49.665491032675 | 2010 | 49.651796714392 | 2009 | 49.636742986588 | 2008 | 49.620576821015 | 2007 | 49.603149828851 | 2006 | 49.583887039438 | 2005 | 49.563108763788 | 2004 | 49.541072506002 | 2003 | 49.518124863868 | 2002 | 49.498232482968 | 2001 | 49.483425343867 | 2000 | 49.471185457566 | 1999 | 49.459762584035 | 1998 | 49.449684560559 | 1997 | 49.441886943685 | 1996 | 49.435580491356 | 1995 | 49.43036549095 | 1994 | 49.427235239642 | 1993 | 49.42581303825 | 1992 | 49.426251873078 | 1991 | 49.428742254071 | 1990 | 49.43290480009 | 1989 | 49.438436276981 | 1988 | 49.445211353444 | 1987 | 49.452828927134 | 1986 | 49.461211371643 | 1985 | 49.470569634037 | 1984 | 49.481280971014 | 1983 | 49.493012243081 | 1982 | 49.505670610682 | 1981 | 49.533193036763 | 1980 | 49.577935322608 | 1979 | 49.631311439064 | 1978 | 49.694498302198 | 1977 | 49.764095876148 | 1976 | 49.837168083075 | 1975 | 49.91122289904 | 1974 | 49.98489472758 | 1973 | 50.065268895461 | 1972 | 50.124013090579 | 1971 | 50.153402682142 | 1970 | 50.183391059483 | 1969 | 50.212006002237 | 1968 | 50.238695470282 | 1967 | 50.264620375813 | 1966 | 50.289873881751 | 1965 | 50.314606563321 | 1964 | 50.337567676149 | 1963 | 50.358391479805 | 1962 | 50.379164119804 | 1961 | 50.400884397756 | 1960 | 50.422122523985 |
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