Year | Value | 2022 | 52.816359673698 | 2021 | 52.821337162514 | 2020 | 52.808483275511 | 2019 | 52.791483473686 | 2018 | 52.744208240463 | 2017 | 52.674530173572 | 2016 | 52.626352338046 | 2015 | 52.576857604143 | 2014 | 52.501140428109 | 2013 | 52.411999195377 | 2012 | 52.328131513086 | 2011 | 52.246937147853 | 2010 | 52.17386459013 | 2009 | 52.10869858525 | 2008 | 52.038652447415 | 2007 | 51.981624053492 | 2006 | 51.941734911983 | 2005 | 51.906067622227 | 2004 | 51.868738645693 | 2003 | 51.827191009863 | 2002 | 51.775290257402 | 2001 | 51.75064277539 | 2000 | 51.773542695366 | 1999 | 51.8002233673 | 1998 | 51.818960126884 | 1997 | 51.833400144454 | 1996 | 51.847165517819 | 1995 | 51.861480285831 | 1994 | 51.873837604401 | 1993 | 51.875966450706 | 1992 | 51.864783784412 | 1991 | 51.846743801454 | 1990 | 51.832114128961 | 1989 | 51.821424775568 | 1988 | 51.810729190257 | 1987 | 51.805108140025 | 1986 | 51.805438601223 | 1985 | 51.807310989331 | 1984 | 51.81267950827 | 1983 | 51.823871326726 | 1982 | 51.834776055629 | 1981 | 51.844968809198 | 1980 | 51.872941034119 | 1979 | 51.921624814246 | 1978 | 51.981796266648 | 1977 | 52.049440337068 | 1976 | 52.119188000344 | 1975 | 52.192120820076 | 1974 | 52.266018679451 | 1973 | 52.343212070605 | 1972 | 52.429293989335 | 1971 | 52.516051053966 | 1970 | 52.521704342343 | 1969 | 52.448823018673 | 1968 | 52.386559335299 | 1967 | 52.335383132273 | 1966 | 52.291060631871 | 1965 | 52.259421523005 | 1964 | 52.237232074621 | 1963 | 52.21592505003 | 1962 | 52.196820885937 | 1961 | 52.17680510604 | 1960 | 52.158954903192 |
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