Year | Value | 2022 | 50.021849229918 | 2021 | 50.005460721834 | 2020 | 49.98933187598 | 2019 | 49.977156345046 | 2018 | 49.963374277201 | 2017 | 49.94461389934 | 2016 | 49.926868463353 | 2015 | 49.913857374039 | 2014 | 49.893013448964 | 2013 | 49.868816357059 | 2012 | 49.855446099622 | 2011 | 49.8482255577 | 2010 | 49.83951947472 | 2009 | 49.828964145346 | 2008 | 49.819295299797 | 2007 | 49.81032181186 | 2006 | 49.801320432047 | 2005 | 49.79298304471 | 2004 | 49.78552359605 | 2003 | 49.777083326608 | 2002 | 49.766527045922 | 2001 | 49.735576066519 | 2000 | 49.702194899406 | 1999 | 49.682466296069 | 1998 | 49.655702400857 | 1997 | 49.621306750496 | 1996 | 49.581962022494 | 1995 | 49.532731957033 | 1994 | 49.485733931773 | 1993 | 49.450592493848 | 1992 | 49.415237419724 | 1991 | 49.37654672863 | 1990 | 49.333605294849 | 1989 | 49.287491800071 | 1988 | 49.280059911901 | 1987 | 49.338047112816 | 1986 | 49.421995633277 | 1985 | 49.509278027477 | 1984 | 49.598896469956 | 1983 | 49.690893780883 | 1982 | 49.785118139433 | 1981 | 49.881934117435 | 1980 | 49.980333510539 | 1979 | 50.079256872171 | 1978 | 50.178299943744 | 1977 | 50.276296642938 | 1976 | 50.372571170259 | 1975 | 50.42538575007 | 1974 | 50.435246650188 | 1973 | 50.445215070779 | 1972 | 50.455815413447 | 1971 | 50.467359219107 | 1970 | 50.479985063047 | 1969 | 50.493317154081 | 1968 | 50.507452954223 | 1967 | 50.521347730365 | 1966 | 50.534583686502 | 1965 | 50.547299303309 | 1964 | 50.558924409972 | 1963 | 50.570088964505 | 1962 | 50.580314972379 | 1961 | 50.589465166479 | 1960 | 50.598013487898 |
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