Year | Value | 2022 | 49.725863124025 | 2021 | 49.696148548487 | 2020 | 49.658286087597 | 2019 | 49.641090222182 | 2018 | 49.652939544477 | 2017 | 49.668928963178 | 2016 | 49.688957374229 | 2015 | 49.713647390315 | 2014 | 49.746406119176 | 2013 | 49.789954973773 | 2012 | 49.83934563385 | 2011 | 49.890452694378 | 2010 | 49.945359602119 | 2009 | 49.948276575495 | 2008 | 49.896784451256 | 2007 | 49.842684227706 | 2006 | 49.786824323154 | 2005 | 49.729112795363 | 2004 | 49.668538334901 | 2003 | 49.6056788309 | 2002 | 49.544312797134 | 2001 | 49.484885126965 | 2000 | 49.443857474439 | 1999 | 49.42144001925 | 1998 | 49.399084955115 | 1997 | 49.379366885136 | 1996 | 49.360941669844 | 1995 | 49.345143351215 | 1994 | 49.336243044916 | 1993 | 49.333340199921 | 1992 | 49.337621322235 | 1991 | 49.373062607931 | 1990 | 49.383588277498 | 1989 | 49.3287445088 | 1988 | 49.268091775971 | 1987 | 49.212188560065 | 1986 | 49.163531529807 | 1985 | 49.118921167919 | 1984 | 49.070566800859 | 1983 | 49.02244750181 | 1982 | 48.978734851616 | 1981 | 48.939931703907 | 1980 | 48.948206128172 | 1979 | 49.009681081348 | 1978 | 49.082651349931 | 1977 | 49.152977978162 | 1976 | 49.224925264664 | 1975 | 49.301610843954 | 1974 | 49.396672368216 | 1973 | 49.504630541872 | 1972 | 49.609768579973 | 1971 | 49.710376875645 | 1970 | 49.818452504032 | 1969 | 49.903931609463 | 1968 | 49.949923797082 | 1967 | 49.995063324088 | 1966 | 50.043493549999 | 1965 | 50.099200671512 | 1964 | 50.158196753527 | 1963 | 50.217474863952 | 1962 | 50.287977710317 | 1961 | 50.371705579317 | 1960 | 50.445827817468 |
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