Year | Value | 2022 | 49.927668610645 | 2021 | 49.91111811197 | 2020 | 49.897140920525 | 2019 | 49.876578812753 | 2018 | 49.841577786659 | 2017 | 49.785715109744 | 2016 | 49.729269575199 | 2015 | 49.682346083957 | 2014 | 49.633952018889 | 2013 | 49.585870667606 | 2012 | 49.54451726669 | 2011 | 49.52163663178 | 2010 | 49.515365664553 | 2009 | 49.509653542687 | 2008 | 49.508418506255 | 2007 | 49.497046443258 | 2006 | 49.47065432092 | 2005 | 49.454881000446 | 2004 | 49.449942150542 | 2003 | 49.440792634025 | 2002 | 49.427328246685 | 2001 | 49.414010612659 | 2000 | 49.399711325737 | 1999 | 49.385030728182 | 1998 | 49.372499361635 | 1997 | 49.361692097906 | 1996 | 49.351150417377 | 1995 | 49.341290883749 | 1994 | 49.328337915563 | 1993 | 49.31381703265 | 1992 | 49.301906614922 | 1991 | 49.289058815089 | 1990 | 49.27646845885 | 1989 | 49.266031344105 | 1988 | 49.256401652048 | 1987 | 49.247445308337 | 1986 | 49.239719502487 | 1985 | 49.233283679252 | 1984 | 49.226083354659 | 1983 | 49.217337143628 | 1982 | 49.184533634242 | 1981 | 49.140931816614 | 1980 | 49.114794839933 | 1979 | 49.093445022857 | 1978 | 49.07481958654 | 1977 | 49.061544866915 | 1976 | 49.051944836443 | 1975 | 49.042713167686 | 1974 | 49.032802518627 | 1973 | 49.006499108825 | 1972 | 48.979115744834 | 1971 | 48.96623489759 | 1970 | 48.948244864579 | 1969 | 48.924757222774 | 1968 | 48.89917745063 | 1967 | 48.869359772132 | 1966 | 48.840789151504 | 1965 | 48.816185525396 | 1964 | 48.79135380905 | 1963 | 48.764232460465 | 1962 | 48.735351108632 | 1961 | 48.706144163127 | 1960 | 48.68206906005 |
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