Year | Value | 2022 | 50.544334869543 | 2021 | 50.50752898941 | 2020 | 50.461444049345 | 2019 | 50.414092270718 | 2018 | 50.364419514973 | 2017 | 50.320472834318 | 2016 | 50.282175891168 | 2015 | 50.249825448753 | 2014 | 50.224795217528 | 2013 | 50.200953340706 | 2012 | 50.17563030816 | 2011 | 50.149413192305 | 2010 | 50.124060500459 | 2009 | 50.095330072566 | 2008 | 50.061998294327 | 2007 | 50.03025784069 | 2006 | 50.003499731257 | 2005 | 49.980732155589 | 2004 | 49.961652007496 | 2003 | 49.942167080799 | 2002 | 49.924189515513 | 2001 | 49.904753590636 | 2000 | 49.885022058334 | 1999 | 49.873834645696 | 1998 | 49.867513019905 | 1997 | 49.863789834349 | 1996 | 49.862981351765 | 1995 | 49.8620409579 | 1994 | 49.859462433817 | 1993 | 49.858478847162 | 1992 | 49.862019981101 | 1991 | 49.867419577386 | 1990 | 49.872477156239 | 1989 | 49.87377623125 | 1988 | 49.871978647683 | 1987 | 49.871051640178 | 1986 | 49.870370270836 | 1985 | 49.868781742923 | 1984 | 49.865836807302 | 1983 | 49.860911193708 | 1982 | 49.853761162355 | 1981 | 49.84587323558 | 1980 | 49.837319005107 | 1979 | 49.828566382187 | 1978 | 49.819198677183 | 1977 | 49.808603497968 | 1976 | 49.799205549829 | 1975 | 49.789817193439 | 1974 | 49.77839549492 | 1973 | 49.765774977215 | 1972 | 49.752201631937 | 1971 | 49.738272225931 | 1970 | 49.72339774426 | 1969 | 49.707278908507 | 1968 | 49.689411837018 | 1967 | 49.670176019611 | 1966 | 49.649299723246 | 1965 | 49.627069721757 | 1964 | 49.605909852953 | 1963 | 49.585058553836 | 1962 | 49.562204237977 | 1961 | 49.538394526225 | 1960 | 49.512568259385 |
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