| Year | Value | | 2022 | 84.328483416986 | | 2021 | 84.323966819114 | | 2020 | 84.312974761181 | | 2019 | 84.42244004463 | | 2018 | 84.871888817092 | | 2017 | 84.708577317515 | | 2016 | 84.545706784193 | | 2015 | 84.98142866099 | | 2014 | 84.725333855827 | | 2013 | 85.347227434261 | | 2012 | 85.317361776447 | | 2011 | 85.790693658333 | | 2010 | 85.975159875719 | | 2009 | 86.376602752518 | | 2008 | 86.635740738317 | | 2007 | 86.594481750865 | | 2006 | 86.757767054172 | | 2005 | 86.990570733642 | | 2004 | 86.891761040274 | | 2003 | 87.168808261601 | | 2002 | 87.671148784345 | | 2001 | 87.786522145632 | | 2000 | 87.716658557997 | | 1999 | 87.370381305758 | | 1998 | 87.479302277614 | | 1997 | 87.005178732217 | | 1996 | 86.920158897809 | | 1995 | 86.483292236212 | | 1994 | 86.524049195344 | | 1993 | 86.852844838327 | | 1992 | 86.715279485098 | | 1991 | 86.011503797209 |
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