| Year | Value | | 2022 | 87.324533642074 | | 2021 | 87.491623666034 | | 2020 | 87.708937039753 | | 2019 | 89.172098953748 | | 2018 | 89.583437815922 | | 2017 | 89.378575831551 | | 2016 | 89.183001827653 | | 2015 | 88.991900577347 | | 2014 | 88.674719415368 | | 2013 | 88.724179294177 | | 2012 | 88.265820190921 | | 2011 | 87.855922614483 | | 2010 | 87.683240856313 | | 2009 | 87.381168791008 | | 2008 | 87.789427575585 | | 2007 | 87.533820757394 | | 2006 | 87.285371711044 | | 2005 | 86.306369455219 | | 2004 | 85.561972142025 | | 2003 | 86.684182705371 | | 2002 | 86.218179174792 | | 2001 | 85.361858959861 | | 2000 | 84.773449505728 | | 1999 | 84.29753305222 | | 1998 | 83.978333802963 | | 1997 | 82.52667445899 | | 1996 | 82.157366852928 | | 1995 | 83.32868852525 | | 1994 | 83.603167167487 | | 1993 | 81.889910528648 | | 1992 | 79.464719102454 | | 1991 | 79.950055278884 |
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