| Year | Value | | 2022 | 85.578283293745 | | 2021 | 85.677124789097 | | 2020 | 85.494902375467 | | 2019 | 85.43472824206 | | 2018 | 85.331130420634 | | 2017 | 85.029362587876 | | 2016 | 84.733874181023 | | 2015 | 84.470519586033 | | 2014 | 84.279763525125 | | 2013 | 84.151336526713 | | 2012 | 84.057215187787 | | 2011 | 84.010724039132 | | 2010 | 83.850331072785 | | 2009 | 83.915791722051 | | 2008 | 83.878212217176 | | 2007 | 83.545021044385 | | 2006 | 83.285489944366 | | 2005 | 83.18470339132 | | 2004 | 83.076268138057 | | 2003 | 83.06184803597 | | 2002 | 83.213597133626 | | 2001 | 83.110444333297 | | 2000 | 82.932341930099 | | 1999 | 82.540059663763 | | 1998 | 82.186093525479 | | 1997 | 81.936669659613 | | 1996 | 81.821300137136 | | 1995 | 81.699680502118 | | 1994 | 81.653038071135 | | 1993 | 81.884799644868 | | 1992 | 81.802227961652 | | 1991 | 82.041552682311 |
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