Year | Value | 2022 | 49.258245750287 | 2021 | 49.238832878563 | 2020 | 49.217176488262 | 2019 | 49.199011650859 | 2018 | 49.18531612613 | 2017 | 49.172239966402 | 2016 | 49.158075873556 | 2015 | 49.144667186148 | 2014 | 49.135558991252 | 2013 | 49.12733574862 | 2012 | 49.117584991651 | 2011 | 49.108042646935 | 2010 | 49.098608448796 | 2009 | 49.088364874416 | 2008 | 49.076557288247 | 2007 | 49.066270058358 | 2006 | 49.05899620782 | 2005 | 49.054331842346 | 2004 | 49.051852042545 | 2003 | 49.050192847408 | 2002 | 49.049386130088 | 2001 | 49.049284158133 | 2000 | 49.050312052258 | 1999 | 49.051878259986 | 1998 | 49.054108089063 | 1997 | 49.058167233464 | 1996 | 49.060329171642 | 1995 | 49.057913992474 | 1994 | 49.054575750966 | 1993 | 49.050779189134 | 1992 | 49.045736271754 | 1991 | 49.043094221286 | 1990 | 49.042162406925 | 1989 | 49.039100324702 | 1988 | 49.034495401557 | 1987 | 49.028134920073 | 1986 | 49.021807263698 | 1985 | 49.005058799929 | 1984 | 48.980987621172 | 1983 | 48.959833912119 | 1982 | 48.940332189314 | 1981 | 48.929223109236 | 1980 | 48.929480725616 | 1979 | 48.927728319406 | 1978 | 48.918207876238 | 1977 | 48.910895716251 | 1976 | 48.902809481895 | 1975 | 48.896037360719 | 1974 | 48.899983057234 | 1973 | 48.909462486457 | 1972 | 48.919058807278 | 1971 | 48.916450249305 | 1970 | 48.909787425778 | 1969 | 48.909716156375 | 1968 | 48.905509705132 | 1967 | 48.900750757178 | 1966 | 48.896197494899 | 1965 | 48.889254170507 | 1964 | 48.884402353579 | 1963 | 48.883739393465 | 1962 | 48.882855577042 | 1961 | 48.881331484062 | 1960 | 48.878939593902 |
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