Year | Value | 2022 | 50.268781089125 | 2021 | 50.267439102254 | 2020 | 50.272386686363 | 2019 | 50.274036279904 | 2018 | 50.270932740393 | 2017 | 50.271126362053 | 2016 | 50.275178600266 | 2015 | 50.277358732911 | 2014 | 50.274023526663 | 2013 | 50.266637298193 | 2012 | 50.257737094151 | 2011 | 50.248487440323 | 2010 | 50.23789545281 | 2009 | 50.221546868246 | 2008 | 50.195906549133 | 2007 | 50.170018227627 | 2006 | 50.145810557942 | 2005 | 50.122534418208 | 2004 | 50.105390275622 | 2003 | 50.090976059386 | 2002 | 50.077778314472 | 2001 | 50.065541049083 | 2000 | 50.056097615654 | 1999 | 50.046873919987 | 1998 | 50.032214092714 | 1997 | 50.018842617943 | 1996 | 50.006866653702 | 1995 | 49.995234544631 | 1994 | 49.989174614942 | 1993 | 49.989731866582 | 1992 | 49.994872084339 | 1991 | 50.002826978648 | 1990 | 50.011569401862 | 1989 | 50.018293270812 | 1988 | 50.016793518558 | 1987 | 50.014649797957 | 1986 | 50.01918478821 | 1985 | 50.023555094739 | 1984 | 50.023868384658 | 1983 | 50.022943509561 | 1982 | 50.024701985318 | 1981 | 50.023508879569 | 1980 | 50.020168806387 | 1979 | 50.014521697297 | 1978 | 50.005517080529 | 1977 | 49.997310461409 | 1976 | 49.986957569624 | 1975 | 49.964634099433 | 1974 | 49.95176191328 | 1973 | 49.953910499993 | 1972 | 49.952421226038 | 1971 | 49.901538497369 | 1970 | 49.85173698462 | 1969 | 49.854731752197 | 1968 | 49.860224542571 | 1967 | 49.866416967607 | 1966 | 49.871680498345 | 1965 | 49.876027887624 | 1964 | 49.879767235912 | 1963 | 49.88278587078 | 1962 | 49.885382726194 | 1961 | 49.887213876586 | 1960 | 49.889606718792 |
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