| Year | Value | | 2021 | 4.8145493375627 | | 2020 | -1.4643301921189 | | 2019 | 2.9278255203138 | | 2018 | 2.9522905525268 | | 2017 | 5.2971596339376 | | 2016 | 5.6424233153071 | | 2015 | 6.2791984355197 | | 2014 | 5.4787674694219 | | 2013 | 4.8486481393578 | | 2012 | 6.7101868080593 | | 2011 | 2.9039218159142 | | 2010 | 7.1972599468674 | | 2009 | 5.3500180018086 | | 2008 | 1.3433018061751 | | 2007 | 13.868702847476 | | 2006 | 8.019593425122 | | 2005 | 4.6226449625428 | | 2004 | 11.26343935556 | | 2003 | -1.6904249352507 | | 2002 | 13.365457447508 | | 2001 | 2.9918457649279 | | 2000 | 2.1270208447532 | | 1999 | 0.81174651739913 | | 1998 | -7.7789027016224 | | 1997 | 1.7142679834768 | | 1996 | -1.7255392090667 |
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