Year | Value | 2022 | 49.914676301294 | 2021 | 49.905156812627 | 2020 | 49.902001155769 | 2019 | 49.897497643289 | 2018 | 49.892760983989 | 2017 | 49.886438284166 | 2016 | 49.878775105287 | 2015 | 49.870343219883 | 2014 | 49.860448528549 | 2013 | 49.848738660266 | 2012 | 49.83594806729 | 2011 | 49.821643753625 | 2010 | 49.806928514807 | 2009 | 49.792348300137 | 2008 | 49.7782415968 | 2007 | 49.765506170058 | 2006 | 49.753277669583 | 2005 | 49.742644525723 | 2004 | 49.733828661704 | 2003 | 49.722852033678 | 2002 | 49.709578640905 | 2001 | 49.695340766299 | 2000 | 49.68220433887 | 1999 | 49.671077078906 | 1998 | 49.661876264262 | 1997 | 49.651467403725 | 1996 | 49.639140970555 | 1995 | 49.626352404264 | 1994 | 49.609024538869 | 1993 | 49.592908019174 | 1992 | 49.579854974356 | 1991 | 49.56010267529 | 1990 | 49.53904664798 | 1989 | 49.516037605918 | 1988 | 49.501012250997 | 1987 | 49.492362801271 | 1986 | 49.478546268306 | 1985 | 49.460476183932 | 1984 | 49.441853725235 | 1983 | 49.424386318843 | 1982 | 49.403018259631 | 1981 | 49.375805201293 | 1980 | 49.329459636655 | 1979 | 49.282178051148 | 1978 | 49.263029132258 | 1977 | 49.246674985754 | 1976 | 49.221113060872 | 1975 | 49.19199717579 | 1974 | 49.161528991478 | 1973 | 49.132727376293 | 1972 | 49.10770165586 | 1971 | 49.081955227408 | 1970 | 49.066074465434 | 1969 | 49.055365810404 | 1968 | 49.037567090694 | 1967 | 49.019835436557 | 1966 | 49.000271870922 | 1965 | 48.977599036201 | 1964 | 48.955001382516 | 1963 | 48.93119177136 | 1962 | 48.905078669071 | 1961 | 48.881238525923 | 1960 | 48.861969079964 |
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