| Year | Value | | 2024 | 99.172040950982 | | 2023 | 99.18137530397 | | 2022 | 99.140079336391 | | 2021 | 99.217215599308 | | 2020 | 99.142996883669 | | 2019 | 99.240756083194 | | 2018 | 99.434035768477 | | 2017 | 99.492429578587 | | 2016 | 99.494410495193 | | 2015 | 99.480885006715 | | 2014 | 99.506305913927 | | 2013 | 99.45859123873 | | 2012 | 99.348515356424 | | 2011 | 99.214960572179 | | 2010 | 98.91018100047 | | 2009 | 98.656184714633 | | 2008 | 99.015509077389 | | 2007 | 98.898527212823 | | 2006 | 98.89562749143 | | 2005 | 98.953335740776 | | 2004 | 98.781540315423 | | 2003 | 98.750656255817 | | 2002 | 98.828074125581 | | 2001 | 98.893328732888 | | 2000 | 99.027985605283 | | 1999 | 98.729517773361 | | 1998 | 98.526543211604 | | 1997 | 98.663362663778 | | 1996 | 98.325415421656 | | 1995 | 98.254221997119 | | 1994 | 98.148650547985 | | 1993 | 98.059043209355 | | 1992 | 98.026265102434 | | 1991 | 97.864379232506 |
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