Year | Value | 2022 | 49.496691345255 | 2021 | 49.503023776626 | 2020 | 49.494397097981 | 2019 | 49.490311607795 | 2018 | 49.490678391173 | 2017 | 49.488351391402 | 2016 | 49.485458300842 | 2015 | 49.483513013083 | 2014 | 49.480221871054 | 2013 | 49.477785630536 | 2012 | 49.47411988119 | 2011 | 49.469362493254 | 2010 | 49.4647207943 | 2009 | 49.459569051141 | 2008 | 49.438707482447 | 2007 | 49.402327749654 | 2006 | 49.367265927123 | 2005 | 49.330887822165 | 2004 | 49.29374708204 | 2003 | 49.258631920805 | 2002 | 49.225201303096 | 2001 | 49.189500374123 | 2000 | 49.150822260974 | 1999 | 49.110202986703 | 1998 | 49.110568042357 | 1997 | 49.114202958491 | 1996 | 49.070905795533 | 1995 | 49.0267528047 | 1994 | 48.972396835645 | 1993 | 48.756846991521 | 1992 | 48.29611199176 | 1991 | 47.905093245085 | 1990 | 47.694126054562 | 1989 | 47.47678431087 | 1988 | 47.318090686814 | 1987 | 47.157899277007 | 1986 | 46.938509397275 | 1985 | 46.778821841924 | 1984 | 46.675807997842 | 1983 | 46.561474765481 | 1982 | 46.434785025724 | 1981 | 46.303448267193 | 1980 | 46.213920756695 | 1979 | 46.205117545038 | 1978 | 46.346914116017 | 1977 | 46.549028119447 | 1976 | 46.913219690375 | 1975 | 47.9107516407 | 1974 | 48.693827993372 | 1973 | 48.905223893666 | 1972 | 49.122081542778 | 1971 | 49.356437950135 | 1970 | 49.61795625715 | 1969 | 49.764675342096 | 1968 | 49.784415305773 | 1967 | 49.803896244347 | 1966 | 49.820708245294 | 1965 | 49.83463050626 | 1964 | 49.850012754834 | 1963 | 49.866293069628 | 1962 | 49.881358210105 | 1961 | 49.896357306201 | 1960 | 49.908421206869 |
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