| Year | Value | | 2022 | 83.326958955224 | | 2021 | 83.303744826098 | | 2020 | 83.286759882439 | | 2019 | 83.751927893255 | | 2018 | 83.822889521123 | | 2017 | 83.937522702506 | | 2016 | 83.981636357166 | | 2015 | 84.081245837816 | | 2014 | 84.330434413261 | | 2013 | 84.529807350852 | | 2012 | 84.761251372119 | | 2011 | 84.863296080273 | | 2010 | 85.299679119872 | | 2009 | 85.70679682904 | | 2008 | 85.718145674914 | | 2007 | 85.330758411288 | | 2006 | 85.026856007652 | | 2005 | 84.512877740118 | | 2004 | 84.044798413188 | | 2003 | 84.732677806898 | | 2002 | 83.671617467314 | | 2001 | 85.053240840302 | | 2000 | 84.082604641786 | | 1999 | 82.924924149506 | | 1998 | 83.971426864324 | | 1997 | 83.714801518956 | | 1996 | 81.766315926308 | | 1995 | 84.137409734046 | | 1994 | 84.112520117869 | | 1993 | 85.262726103797 | | 1992 | 85.770862800566 | | 1991 | 86.598204106089 |
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