Year | Value | 2022 | 51.628486453742 | 2021 | 51.651964760955 | 2020 | 51.62109548392 | 2019 | 51.593997831718 | 2018 | 51.58043519939 | 2017 | 51.570616827284 | 2016 | 51.570728494349 | 2015 | 51.57908797609 | 2014 | 51.583434671099 | 2013 | 51.582180610455 | 2012 | 51.579615315359 | 2011 | 51.578036610265 | 2010 | 51.574016124052 | 2009 | 51.565025032837 | 2008 | 51.558542907229 | 2007 | 51.560400169107 | 2006 | 51.570363015181 | 2005 | 51.586306714158 | 2004 | 51.604896472338 | 2003 | 51.621171324667 | 2002 | 51.627175649681 | 2001 | 51.603232283936 | 2000 | 51.558576335012 | 1999 | 51.514326394107 | 1998 | 51.465116440676 | 1997 | 51.413315710714 | 1996 | 51.363985577755 | 1995 | 51.316820820397 | 1994 | 51.275137437847 | 1993 | 51.241432402638 | 1992 | 51.21340269707 | 1991 | 51.192322270408 | 1990 | 51.178784557909 | 1989 | 51.172518566757 | 1988 | 51.171202125014 | 1987 | 51.170847354707 | 1986 | 51.169881936424 | 1985 | 51.168693707622 | 1984 | 51.170024781174 | 1983 | 51.175945361319 | 1982 | 51.186215256639 | 1981 | 51.200653671483 | 1980 | 51.220859956039 | 1979 | 51.246784673994 | 1978 | 51.27752548912 | 1977 | 51.31417474295 | 1976 | 51.323502707622 | 1975 | 51.307148089278 | 1974 | 51.298266640134 | 1973 | 51.289382154145 | 1972 | 51.277187427894 | 1971 | 51.265514580017 | 1970 | 51.255838966545 | 1969 | 51.246697333023 | 1968 | 51.236706710807 | 1967 | 51.224635290236 | 1966 | 51.216427993615 | 1965 | 51.225035926004 | 1964 | 51.247776702557 | 1963 | 51.274211117334 | 1962 | 51.304673594658 | 1961 | 51.338815934845 | 1960 | 51.375576389391 |
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