Year | Value | 2022 | 51.587917298141 | 2021 | 51.643318634993 | 2020 | 51.623740650331 | 2019 | 51.613152534106 | 2018 | 51.611168289922 | 2017 | 51.609698248859 | 2016 | 51.605223414558 | 2015 | 51.598855252954 | 2014 | 51.594158002494 | 2013 | 51.589631125449 | 2012 | 51.583195243686 | 2011 | 51.575116931019 | 2010 | 51.56793524157 | 2009 | 51.562334450387 | 2008 | 51.552067158423 | 2007 | 51.531249492172 | 2006 | 51.503449837406 | 2005 | 51.478833513485 | 2004 | 51.459566760757 | 2003 | 51.442279696266 | 2002 | 51.425679131025 | 2001 | 51.408796379327 | 2000 | 51.449881183805 | 1999 | 51.482243911321 | 1998 | 51.453103557348 | 1997 | 51.43018580258 | 1996 | 51.410198292729 | 1995 | 51.38964196063 | 1994 | 51.367508073324 | 1993 | 51.347368177119 | 1992 | 51.32492769842 | 1991 | 51.298545967863 | 1990 | 51.274420056297 | 1989 | 51.254541070955 | 1988 | 51.230543385134 | 1987 | 51.215240094978 | 1986 | 51.214799406723 | 1985 | 51.219185694351 | 1984 | 51.22935816139 | 1983 | 51.240876807433 | 1982 | 51.253053305893 | 1981 | 51.260349265771 | 1980 | 51.26416226104 | 1979 | 51.267659356758 | 1978 | 51.267210079936 | 1977 | 51.267789188585 | 1976 | 51.277031126122 | 1975 | 51.297259538929 | 1974 | 51.325312550227 | 1973 | 51.35068944526 | 1972 | 51.373784930823 | 1971 | 51.394988142122 | 1970 | 51.402651539302 | 1969 | 51.404189757646 | 1968 | 51.412227366385 | 1967 | 51.425114988644 | 1966 | 51.440712332635 | 1965 | 51.461985382372 | 1964 | 51.488089724114 | 1963 | 51.516069863229 | 1962 | 51.548030370985 | 1961 | 51.583556735026 | 1960 | 51.622335051389 |
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