Year | Value | 2022 | 49.799375070837 | 2021 | 49.777891853839 | 2020 | 49.757488033613 | 2019 | 49.735170819585 | 2018 | 49.711385323857 | 2017 | 49.686790582807 | 2016 | 49.66008987915 | 2015 | 49.63357991158 | 2014 | 49.60592096558 | 2013 | 49.576774897099 | 2012 | 49.547756790574 | 2011 | 49.511258864188 | 2010 | 49.471337497226 | 2009 | 49.437858412636 | 2008 | 49.403087354353 | 2007 | 49.367502215958 | 2006 | 49.333578746523 | 2005 | 49.302394929091 | 2004 | 49.275039736463 | 2003 | 49.261678356449 | 2002 | 49.250914608546 | 2001 | 49.231666514626 | 2000 | 49.215846511358 | 1999 | 49.207005806628 | 1998 | 49.201090926727 | 1997 | 49.193051651072 | 1996 | 49.201621077639 | 1995 | 49.22559607771 | 1994 | 49.263409809345 | 1993 | 49.306934499766 | 1992 | 49.34279308554 | 1991 | 49.37000963266 | 1990 | 49.577391999298 | 1989 | 49.733649704897 | 1988 | 49.752073974879 | 1987 | 49.766886453618 | 1986 | 49.779431535306 | 1985 | 49.795555166619 | 1984 | 49.812666211019 | 1983 | 49.861769024598 | 1982 | 49.923276105415 | 1981 | 49.964718121919 | 1980 | 50.020055181508 | 1979 | 50.085574168011 | 1978 | 50.156327144137 | 1977 | 50.234772851186 | 1976 | 50.31300880661 | 1975 | 50.392251404615 | 1974 | 50.451551175287 | 1973 | 50.485595158138 | 1972 | 50.52242220124 | 1971 | 50.567705829157 | 1970 | 50.61360529065 | 1969 | 50.656893046324 | 1968 | 50.703694187569 | 1967 | 50.749065744558 | 1966 | 50.796362989135 | 1965 | 50.84373288589 | 1964 | 50.888346610134 | 1963 | 50.934797401339 | 1962 | 50.999719450458 | 1961 | 51.083815090922 | 1960 | 51.169454348449 |
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