Year | Value | 2022 | 50.691243885002 | 2021 | 50.655277674059 | 2020 | 50.619650677902 | 2019 | 50.587489267357 | 2018 | 50.559873890384 | 2017 | 50.532963735604 | 2016 | 50.504787423555 | 2015 | 50.477631030512 | 2014 | 50.45108283873 | 2013 | 50.424617511085 | 2012 | 50.400195539071 | 2011 | 50.375436545082 | 2010 | 50.346754147413 | 2009 | 50.313235427403 | 2008 | 50.276714296017 | 2007 | 50.240834136114 | 2006 | 50.20885269777 | 2005 | 50.181074172051 | 2004 | 50.155392760601 | 2003 | 50.131445498012 | 2002 | 50.107700985111 | 2001 | 50.084226196306 | 2000 | 50.046795456975 | 1999 | 49.997635665121 | 1998 | 49.948697777183 | 1997 | 49.897277364626 | 1996 | 49.843672977173 | 1995 | 49.789735797146 | 1994 | 49.737743873789 | 1993 | 49.687183433164 | 1992 | 49.638334730771 | 1991 | 49.589362640467 | 1990 | 49.568188280182 | 1989 | 49.578396989306 | 1988 | 49.592701511749 | 1987 | 49.610052775742 | 1986 | 49.628498943243 | 1985 | 49.646362875072 | 1984 | 49.663863802336 | 1983 | 49.676853707415 | 1982 | 49.681967452976 | 1981 | 49.682256366473 | 1980 | 49.677284223424 | 1979 | 49.665437633107 | 1978 | 49.647723406439 | 1977 | 49.6232634285 | 1976 | 49.592963964424 | 1975 | 49.562643815322 | 1974 | 49.537605219335 | 1973 | 49.51985744793 | 1972 | 49.498381801236 | 1971 | 49.466769229308 | 1970 | 49.435921528945 | 1969 | 49.408526952497 | 1968 | 49.378607269094 | 1967 | 49.343635896182 | 1966 | 49.305065968376 | 1965 | 49.266834337778 | 1964 | 49.231225083504 | 1963 | 49.197659208262 | 1962 | 49.182471098388 | 1961 | 49.203526036325 | 1960 | 49.245658602329 |
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