| Year | Value | | 2022 | 93.438083536201 | | 2021 | 93.422813297139 | | 2020 | 93.406723298293 | | 2019 | 93.501783667529 | | 2018 | 93.717708333333 | | 2017 | 93.598740405014 | | 2016 | 93.584852983418 | | 2015 | 93.291163761791 | | 2014 | 93.584186685267 | | 2013 | 93.213467252167 | | 2012 | 92.688626341957 | | 2011 | 92.519241681337 | | 2010 | 92.051774545499 | | 2009 | 92.062849223877 | | 2008 | 92.567342649583 | | 2007 | 91.375388725326 | | 2006 | 90.682914731479 | | 2005 | 89.64237189441 | | 2004 | 88.36699505255 | | 2003 | 89.143242740134 | | 2002 | 89.50730483315 | | 2001 | 89.268064323083 | | 2000 | 88.217028115637 | | 1999 | 89.138283240969 | | 1998 | 90.330940379818 | | 1997 | 90.352480951116 | | 1996 | 89.266934070306 | | 1995 | 89.215773693421 | | 1994 | 89.129645112002 | | 1993 | 89.010823450005 | | 1992 | 88.871784432966 | | 1991 | 88.802064427563 |
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