| Year | Value | | 2022 | 89.308568558137 | | 2021 | 89.693875933353 | | 2020 | 90.601538820238 | | 2019 | 91.234326045098 | | 2018 | 91.394534230422 | | 2017 | 90.707108219481 | | 2016 | 89.938521851472 | | 2015 | 90.216058899175 | | 2014 | 91.243011212612 | | 2013 | 91.150389858525 | | 2012 | 91.119793472188 | | 2011 | 91.440913219422 | | 2010 | 91.82636173048 | | 2009 | 91.280460788658 | | 2008 | 93.213166953933 | | 2007 | 92.54099101456 | | 2006 | 92.025727244292 | | 2005 | 91.979676738724 | | 2004 | 91.822271173879 | | 2003 | 91.892725675563 | | 2002 | 91.841644114018 | | 2001 | 92.475701186766 | | 2000 | 90.324087400946 | | 1999 | 90.626809292809 | | 1998 | 90.366919044846 | | 1997 | 90.533590201311 | | 1996 | 90.013147737142 | | 1995 | 88.460717270492 | | 1994 | 88.893145076821 | | 1993 | 88.681510326457 | | 1992 | 89.556172887038 | | 1991 | 88.881374272961 |
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