| Year | Value | | 2021 | 74.796378268719 | | 2020 | 76.628518942563 | | 2019 | 67.123153157975 | | 2018 | 67.344762071059 | | 2017 | 65.72780851576 | | 2016 | 66.905932571848 | | 2015 | 73.548368624032 | | 2014 | 67.98549415049 | | 2013 | 75.15600883399 | | 2012 | 55.419259635708 | | 2011 | 60.702512775566 | | 2010 | 65.757519770096 | | 2009 | 70.979776415088 | | 2008 | 65.412561916998 | | 2007 | 74.726066158829 | | 2006 | 59.738845487603 | | 2005 | 76.190329546181 | | 2004 | 70.110717318036 | | 2003 | 68.336605716356 | | 2002 | 67.239626434851 | | 2001 | 62.81950982621 | | 2000 | 72.683215163609 | | 1999 | 88.806197087656 | | 1998 | 89.328230971571 | | 1997 | 87.285479099518 | | 1996 | 77.435768862522 | | 1995 | 64.68830274953 | | 1994 | 65.996531279157 | | 1993 | 76.040272241275 | | 1992 | 89.389533515763 | | 1991 | 80.674036067456 | | 1990 | 81.660349017979 |
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