| Year | Value | | 2024 | 47.666891181705 | | 2023 | 47.616539730988 | | 2022 | 47.561704931516 | | 2021 | 47.511440311296 | | 2020 | 47.469831207011 | | 2019 | 47.431520214823 | | 2018 | 47.394284806656 | | 2017 | 47.359429702598 | | 2016 | 47.326389454897 | | 2015 | 47.295873682453 | | 2014 | 47.267880488406 | | 2013 | 47.238034998194 | | 2012 | 47.271525668143 | | 2011 | 47.334860611924 | | 2010 | 47.355210893953 | | 2009 | 47.3687702535 | | 2008 | 47.383238869833 | | 2007 | 47.400683439578 | | 2006 | 47.386915179619 | | 2005 | 47.392243366427 | | 2004 | 47.447964951347 | | 2003 | 47.483004453284 | | 2002 | 47.494993444964 | | 2001 | 47.51891115705 | | 2000 | 47.586106858739 | | 1999 | 47.647125317543 | | 1998 | 47.632094264283 | | 1997 | 47.577870131369 | | 1996 | 47.535349956028 | | 1995 | 47.523376480544 | | 1994 | 47.60656251529 | | 1993 | 47.801006750465 | | 1992 | 48.2169684488 | | 1991 | 48.533039751307 | | 1990 | 48.554168661777 | | 1989 | 48.577887613906 | | 1988 | 48.632696287859 | | 1987 | 48.773108454466 | | 1986 | 48.893051515172 | | 1985 | 48.932053677223 | | 1984 | 48.965308655628 | | 1983 | 48.997209820602 | | 1982 | 48.943371483805 | | 1981 | 48.836881490682 | | 1980 | 48.02997399771 | | 1979 | 47.330064262706 | | 1978 | 47.849822153792 | | 1977 | 48.408089106883 | | 1976 | 48.652925098742 |
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