Year | Value | 2022 | 49.412218032052 | 2021 | 49.404442780987 | 2020 | 49.390230669569 | 2019 | 49.365946474686 | 2018 | 49.337707219759 | 2017 | 49.303685091519 | 2016 | 49.259055917517 | 2015 | 49.214128907935 | 2014 | 49.183109216617 | 2013 | 49.155137315237 | 2012 | 49.12534663352 | 2011 | 49.097819183744 | 2010 | 49.069588316533 | 2009 | 49.043767203022 | 2008 | 49.01267561896 | 2007 | 48.977355257607 | 2006 | 48.954047196003 | 2005 | 48.935765451897 | 2004 | 48.917636307055 | 2003 | 48.895518482774 | 2002 | 48.865091616422 | 2001 | 48.833481559953 | 2000 | 48.803960581963 | 1999 | 48.776815214662 | 1998 | 48.754876256029 | 1997 | 48.73365327203 | 1996 | 48.708807001673 | 1995 | 48.683256645581 | 1994 | 48.658030181842 | 1993 | 48.627572111897 | 1992 | 48.594172968082 | 1991 | 48.55821489816 | 1990 | 48.520508688882 | 1989 | 48.486154125058 | 1988 | 48.460859979287 | 1987 | 48.445067653709 | 1986 | 48.429477456258 | 1985 | 48.417447357551 | 1984 | 48.408766695864 | 1983 | 48.39670962139 | 1982 | 48.378480341572 | 1981 | 48.358485082393 | 1980 | 48.348711077374 | 1979 | 48.3518337864 | 1978 | 48.35870297113 | 1977 | 48.345794102608 | 1976 | 48.337409782377 | 1975 | 48.349502734662 | 1974 | 48.351481779637 | 1973 | 48.339600434275 | 1972 | 48.311501000791 | 1971 | 48.28419937109 | 1970 | 48.303431083217 | 1969 | 48.331944683815 | 1968 | 48.326618457858 | 1967 | 48.31599346054 | 1966 | 48.305170013359 | 1965 | 48.287433923318 | 1964 | 48.265862602326 | 1963 | 48.245042268445 | 1962 | 48.221995952069 | 1961 | 48.194083239176 | 1960 | 48.160128283929 |
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