| Year | Value | | 2022 | 90.312455036204 | | 2021 | 90.144218098422 | | 2020 | 90.118568803807 | | 2019 | 90.067687626452 | | 2018 | 89.837197073757 | | 2017 | 89.690360975466 | | 2016 | 89.535056623695 | | 2015 | 89.135818070047 | | 2014 | 88.775344422697 | | 2013 | 88.654837980359 | | 2012 | 88.424019396998 | | 2011 | 88.324110951426 | | 2010 | 87.905738391854 | | 2009 | 87.561997178793 | | 2008 | 87.198904940438 | | 2007 | 86.874885698784 | | 2006 | 86.456283091367 | | 2005 | 85.674363328772 | | 2004 | 85.345260860839 | | 2003 | 85.240668863247 | | 2002 | 85.012922896858 | | 2001 | 84.580161802687 | | 2000 | 83.905601896371 | | 1999 | 83.389877281436 | | 1998 | 83.106002401324 | | 1997 | 82.217476095117 | | 1996 | 82.053649603013 | | 1995 | 81.508437224426 | | 1994 | 81.140556849995 | | 1993 | 80.651160499766 | | 1992 | 79.536979322846 | | 1991 | 78.536659178638 |
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