Year | Value | 2022 | 49.848754648048 | 2021 | 49.849479957333 | 2020 | 49.848679338332 | 2019 | 49.846411823864 | 2018 | 49.84325585578 | 2017 | 49.83702973111 | 2016 | 49.827552073484 | 2015 | 49.816557236191 | 2014 | 49.806919436026 | 2013 | 49.799208610967 | 2012 | 49.791579772691 | 2011 | 49.784277238025 | 2010 | 49.775929571624 | 2009 | 49.768787369563 | 2008 | 49.762099401025 | 2007 | 49.751934359829 | 2006 | 49.739902550905 | 2005 | 49.727929256088 | 2004 | 49.716041029644 | 2003 | 49.702975434735 | 2002 | 49.689293472609 | 2001 | 49.680007681164 | 2000 | 49.673376364638 | 1999 | 49.66960568957 | 1998 | 49.671696221378 | 1997 | 49.671459388303 | 1996 | 49.673783099188 | 1995 | 49.676627732093 | 1994 | 49.673194074973 | 1993 | 49.663979433406 | 1992 | 49.652846610764 | 1991 | 49.641816731462 | 1990 | 49.632670804588 | 1989 | 49.627453837483 | 1988 | 49.627315499229 | 1987 | 49.624462972391 | 1986 | 49.614625608079 | 1985 | 49.607157063801 | 1984 | 49.607465393402 | 1983 | 49.61623819752 | 1982 | 49.624879204891 | 1981 | 49.634450337981 | 1980 | 49.643527275458 | 1979 | 49.650189987209 | 1978 | 49.654851453776 | 1977 | 49.657043260893 | 1976 | 49.654202072197 | 1975 | 49.646904721674 | 1974 | 49.638068682358 | 1973 | 49.63162014369 | 1972 | 49.629358437022 | 1971 | 49.626006079687 | 1970 | 49.620919625528 | 1969 | 49.616239857852 | 1968 | 49.611243719021 | 1967 | 49.606766213171 | 1966 | 49.603111523524 | 1965 | 49.600411845036 | 1964 | 49.598530917387 | 1963 | 49.596343289695 | 1962 | 49.593109432833 | 1961 | 49.593373178519 | 1960 | 49.598993810863 |
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