Year | Value | 2022 | 49.523108055556 | 2021 | 49.501761771567 | 2020 | 49.48104542737 | 2019 | 49.457362055793 | 2018 | 49.437810001011 | 2017 | 49.441473656122 | 2016 | 49.456751042937 | 2015 | 49.455495158741 | 2014 | 49.455235415423 | 2013 | 49.445585015925 | 2012 | 49.407556100936 | 2011 | 49.363021756215 | 2010 | 49.306016139514 | 2009 | 49.243073119775 | 2008 | 49.181018616737 | 2007 | 49.111652739669 | 2006 | 49.035527292613 | 2005 | 48.953169489318 | 2004 | 48.867012941434 | 2003 | 48.777145135546 | 2002 | 48.687859888425 | 2001 | 48.599398445303 | 2000 | 48.507483923303 | 1999 | 48.417073422966 | 1998 | 48.423212402069 | 1997 | 48.472933637003 | 1996 | 48.477762399782 | 1995 | 48.493240906051 | 1994 | 48.46366702749 | 1993 | 48.483949932366 | 1992 | 48.607142792299 | 1991 | 48.682636883537 | 1990 | 48.708864180624 | 1989 | 48.736695883633 | 1988 | 48.754683139493 | 1987 | 48.82687493525 | 1986 | 48.894519061172 | 1985 | 48.893227603716 | 1984 | 48.895414529401 | 1983 | 48.887083982134 | 1982 | 48.851839700684 | 1981 | 48.797633647627 | 1980 | 48.737909147207 | 1979 | 48.673301746094 | 1978 | 48.604786242737 | 1977 | 48.531290598107 | 1976 | 48.45028967223 | 1975 | 48.36683852933 | 1974 | 48.282404050245 | 1973 | 48.200109245963 | 1972 | 48.167915687149 | 1971 | 48.186944920054 | 1970 | 48.276393380824 | 1969 | 48.441953885833 | 1968 | 48.612222060413 | 1967 | 48.788546836597 | 1966 | 48.984414365343 | 1965 | 49.151870040355 | 1964 | 49.245750883624 | 1963 | 49.35245524231 | 1962 | 49.478088541475 | 1961 | 49.577595845034 | 1960 | 49.6878314448 |
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