Year | Value | 2022 | 49.978132846186 | 2021 | 49.994557602736 | 2020 | 50.01066812402 | 2019 | 50.022843654954 | 2018 | 50.036625722799 | 2017 | 50.05538610066 | 2016 | 50.073131536647 | 2015 | 50.086142625961 | 2014 | 50.106986551036 | 2013 | 50.131204465741 | 2012 | 50.144532950538 | 2011 | 50.1517744423 | 2010 | 50.16048052528 | 2009 | 50.171035854654 | 2008 | 50.180704700203 | 2007 | 50.18967818814 | 2006 | 50.198702854354 | 2005 | 50.207040714839 | 2004 | 50.21447640395 | 2003 | 50.222941506754 | 2002 | 50.233498395176 | 2001 | 50.264423933481 | 2000 | 50.297805100594 | 1999 | 50.317533703931 | 1998 | 50.344297599143 | 1997 | 50.378664335001 | 1996 | 50.418037977506 | 1995 | 50.467298561421 | 1994 | 50.514266068227 | 1993 | 50.549375134746 | 1992 | 50.584796005785 | 1991 | 50.62345327137 | 1990 | 50.666394705151 | 1989 | 50.712508199929 | 1988 | 50.719902454995 | 1987 | 50.661952887184 | 1986 | 50.577965661505 | 1985 | 50.49068280407 | 1984 | 50.401103530044 | 1983 | 50.309146297719 | 1982 | 50.214881860567 | 1981 | 50.118065882565 | 1980 | 50.019625086325 | 1979 | 49.920743127829 | 1978 | 49.821700056256 | 1977 | 49.723746054735 | 1976 | 49.627385695596 | 1975 | 49.574570465693 | 1974 | 49.564798006524 | 1973 | 49.554784929221 | 1972 | 49.544231020151 | 1971 | 49.532593415005 | 1970 | 49.520014936953 | 1969 | 49.506682845919 | 1968 | 49.4925976721 | 1967 | 49.478704060002 | 1966 | 49.465469255681 | 1965 | 49.452754774977 | 1964 | 49.441075590028 | 1963 | 49.429911035495 | 1962 | 49.419685027621 | 1961 | 49.410593300607 | 1960 | 49.401986512102 |
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