| Year | Value | | 2025 | 87.090096048598 | | 2024 | 86.976615136248 | | 2023 | 86.819703918793 | | 2022 | 86.530334779348 | | 2021 | 85.997496988728 | | 2020 | 84.838529988363 | | 2019 | 85.206167744508 | | 2018 | 84.93017693583 | | 2017 | 85.13311538042 | | 2016 | 85.051930775325 | | 2015 | 85.000568494983 | | 2014 | 85.001979896478 | | 2013 | 84.806253159778 | | 2012 | 84.79537871777 | | 2011 | 84.659889535978 | | 2010 | 84.462625949947 | | 2009 | 84.086121197119 | | 2008 | 84.612046901688 | | 2007 | 84.622389781208 | | 2006 | 84.676416604973 | | 2005 | 84.389726038861 | | 2004 | 84.570016760893 | | 2003 | 84.597576259595 | | 2002 | 84.799101769439 | | 2001 | 84.745257609229 | | 2000 | 83.868557543683 | | 1999 | 83.048698283832 | | 1998 | 82.817429065112 | | 1997 | 82.903272936584 | | 1996 | 83.800156255339 | | 1995 | 84.331981536582 | | 1994 | 84.46671222455 | | 1993 | 84.279344499542 | | 1992 | 84.859425526445 | | 1991 | 85.255191132348 |
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