Year | Value | 2022 | 50.492543404637 | 2021 | 50.482346813426 | 2020 | 50.459228705954 | 2019 | 50.439448928664 | 2018 | 50.434825622601 | 2017 | 50.432453403817 | 2016 | 50.444221506856 | 2015 | 50.456717653371 | 2014 | 50.44565368113 | 2013 | 50.414578687191 | 2012 | 50.367600036424 | 2011 | 50.309092755169 | 2010 | 50.237102342792 | 2009 | 50.150213762292 | 2008 | 50.052303003678 | 2007 | 50.012211373224 | 2006 | 50.034456055545 | 2005 | 50.057012639984 | 2004 | 50.078438265613 | 2003 | 50.097973304533 | 2002 | 50.115218849964 | 2001 | 50.129034304724 | 2000 | 50.13826402424 | 1999 | 50.142907810644 | 1998 | 50.143913838232 | 1997 | 50.143281872391 | 1996 | 50.142946020974 | 1995 | 50.143872636386 | 1994 | 50.146331244904 | 1993 | 50.144319002707 | 1992 | 50.136042272813 | 1991 | 50.127272693458 | 1990 | 50.117931083487 | 1989 | 50.10594325988 | 1988 | 50.092308387911 | 1987 | 50.077890375863 | 1986 | 50.061768755298 | 1985 | 50.043617613352 | 1984 | 50.020984518745 | 1983 | 49.997646984587 | 1982 | 49.979476849603 | 1981 | 49.965498096624 | 1980 | 49.954734643136 | 1979 | 49.936201524282 | 1978 | 49.907449478558 | 1977 | 49.878126522956 | 1976 | 49.840406909464 | 1975 | 49.796389559898 | 1974 | 49.755176518836 | 1973 | 49.716857861972 | 1972 | 49.696157485249 | 1971 | 49.692293714304 | 1970 | 49.701516054973 | 1969 | 49.712469725639 | 1968 | 49.713222876859 | 1967 | 49.714316067474 | 1966 | 49.715847391035 | 1965 | 49.7170371277 | 1964 | 49.717753448367 | 1963 | 49.718253902192 | 1962 | 49.718182588106 | 1961 | 49.718822961729 | 1960 | 49.720439232116 |
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