| Year | Value | | 2022 | 89.484513705873 | | 2021 | 89.649715386157 | | 2020 | 89.938588963694 | | 2019 | 90.200763893745 | | 2018 | 90.325229861933 | | 2017 | 90.654324579908 | | 2016 | 90.861337202536 | | 2015 | 91.176136071507 | | 2014 | 91.386858276123 | | 2013 | 91.545989014617 | | 2012 | 91.799185367853 | | 2011 | 92.150876616316 | | 2010 | 92.392834056374 | | 2009 | 92.53117129364 | | 2008 | 92.991024990824 | | 2007 | 93.111893860055 | | 2006 | 93.236796749969 | | 2005 | 93.277260350622 | | 2004 | 92.979310459114 | | 2003 | 93.269913651406 | | 2002 | 93.167197105707 | | 2001 | 92.91395992844 | | 2000 | 92.937953949446 | | 1999 | 92.457702103036 | | 1998 | 92.580916351408 | | 1997 | 91.95215254071 | | 1996 | 92.126755651374 | | 1995 | 92.42619858837 | | 1994 | 92.071817304789 | | 1993 | 91.744095041239 | | 1992 | 93.84035365574 | | 1991 | 95.697937992654 |
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