| Year | Value | | 2022 | 87.269443884319 | | 2021 | 87.179233072915 | | 2020 | 87.075178153024 | | 2019 | 87.168227968862 | | 2018 | 87.16160797762 | | 2017 | 86.808028834678 | | 2016 | 86.468343649305 | | 2015 | 86.130938702481 | | 2014 | 85.743625169116 | | 2013 | 85.834038935853 | | 2012 | 85.835288502642 | | 2011 | 85.472578862197 | | 2010 | 84.739782452926 | | 2009 | 84.9200686308 | | 2008 | 84.885105783293 | | 2007 | 84.634466444677 | | 2006 | 85.279716961357 | | 2005 | 85.610145667447 | | 2004 | 86.297231161142 | | 2003 | 86.50692476562 | | 2002 | 86.31702087518 | | 2001 | 86.517624853748 | | 2000 | 86.554182728085 | | 1999 | 86.621949809182 | | 1998 | 86.773318990466 | | 1997 | 86.70648482917 | | 1996 | 86.332882532975 | | 1995 | 86.681791088514 | | 1994 | 86.972876727375 | | 1993 | 86.565803538855 | | 1992 | 85.634450598934 | | 1991 | 85.816433494428 |
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