Year | Value | 2022 | 50.330374197613 | 2021 | 50.329490193502 | 2020 | 50.317655960749 | 2019 | 50.297512956209 | 2018 | 50.275944090684 | 2017 | 50.243256976972 | 2016 | 50.210593622022 | 2015 | 50.148926604473 | 2014 | 50.081015125821 | 2013 | 50.027252672787 | 2012 | 49.945060640614 | 2011 | 49.836744460697 | 2010 | 49.742836294792 | 2009 | 49.677022825327 | 2008 | 49.602873310344 | 2007 | 49.559670576075 | 2006 | 49.538107213317 | 2005 | 49.509099513832 | 2004 | 49.460448941431 | 2003 | 49.373104302417 | 2002 | 49.313879613288 | 2001 | 49.298130311615 | 2000 | 49.328096449264 | 1999 | 49.341677749337 | 1998 | 49.273562588828 | 1997 | 49.208792311866 | 1996 | 49.178851990068 | 1995 | 49.173402676414 | 1994 | 49.1892658248 | 1993 | 49.191952548166 | 1992 | 49.1650405092 | 1991 | 49.105199547618 | 1990 | 48.995061203828 | 1989 | 48.874250893357 | 1988 | 48.777019644808 | 1987 | 48.709132422556 | 1986 | 48.665562104463 | 1985 | 48.649260777262 | 1984 | 48.638658862319 | 1983 | 48.643005691769 | 1982 | 48.704728508027 | 1981 | 48.78029373918 | 1980 | 48.841345902716 | 1979 | 48.909162046885 | 1978 | 48.971249262606 | 1977 | 49.025168380007 | 1976 | 49.081314679577 | 1975 | 49.126859805579 | 1974 | 49.165450059336 | 1973 | 49.218181714044 | 1972 | 49.194548065615 | 1971 | 49.068780686082 | 1970 | 49.034012883757 | 1969 | 49.081675185276 | 1968 | 49.110210475721 | 1967 | 49.138753129098 | 1966 | 49.17809864017 | 1965 | 49.225577178481 | 1964 | 49.263856503341 | 1963 | 49.287010148418 | 1962 | 49.318434776084 | 1961 | 49.356732904383 | 1960 | 49.395228030862 |
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