Year | Value | 2022 | 50.036472086011 | 2021 | 50.030402651481 | 2020 | 50.024324666476 | 2019 | 50.01944041895 | 2018 | 50.015065813736 | 2017 | 50.010351567858 | 2016 | 50.004501339342 | 2015 | 49.997128723667 | 2014 | 49.986653873194 | 2013 | 49.97294579178 | 2012 | 49.961017971892 | 2011 | 49.951943112452 | 2010 | 49.94412111014 | 2009 | 49.935026710904 | 2008 | 49.922054226881 | 2007 | 49.906519997347 | 2006 | 49.889961312062 | 2005 | 49.859950264343 | 2004 | 49.815025553604 | 2003 | 49.774782532903 | 2002 | 49.744185032614 | 2001 | 49.715720559717 | 2000 | 49.686667891312 | 1999 | 49.655717241703 | 1998 | 49.584492382161 | 1997 | 49.49438488954 | 1996 | 49.423097344769 | 1995 | 49.350351699797 | 1994 | 49.297581519009 | 1993 | 49.219327074354 | 1992 | 49.147483943914 | 1991 | 49.154577499436 | 1990 | 49.179318498047 | 1989 | 49.197317265279 | 1988 | 49.12911862572 | 1987 | 49.027460078657 | 1986 | 49.025113926108 | 1985 | 49.064814433385 | 1984 | 49.09680699048 | 1983 | 49.058964732296 | 1982 | 49.021478786788 | 1981 | 49.083630653878 | 1980 | 49.183894814229 | 1979 | 49.297021467556 | 1978 | 49.419305327665 | 1977 | 49.546123879798 | 1976 | 49.665587398044 | 1975 | 49.782867889363 | 1974 | 49.90834657688 | 1973 | 49.977068213384 | 1972 | 49.973965892748 | 1971 | 49.956675514386 | 1970 | 49.928139301486 | 1969 | 49.890148269971 | 1968 | 49.853128599115 | 1967 | 49.817431326002 | 1966 | 49.778975595898 | 1965 | 49.744506853596 | 1964 | 49.721655900229 | 1963 | 49.696015102866 | 1962 | 49.679392417754 | 1961 | 49.682261360841 | 1960 | 49.685892999932 |
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