| Year | Value | | 2021 | 6.5090620530895 | | 2020 | -1.9879283233676 | | 2019 | 3.2941122039687 | | 2018 | 3.3527433438314 | | 2017 | 5.6165787146715 | | 2016 | 4.1936791806383 | | 2015 | 4.0645834840015 | | 2014 | 5.0795890324147 | | 2013 | 4.4960646351849 | | 2012 | 6.5128965893726 | | 2011 | 5.2625492662074 | | 2010 | 7.9990475165736 | | 2009 | 4.2026119480503 | | 2008 | 4.7383376313371 | | 2007 | 17.671046237061 | | 2006 | 12.955696263219 | | 2005 | 6.6325762492539 | | 2004 | 14.883670867024 | | 2003 | -1.8380258081919 | | 2002 | 15.796462441741 | | 2001 | 3.3298562766936 | | 2000 | 3.2921677685316 | | 1999 | 1.4281927118792 | | 1998 | -7.3564405467387 | | 1997 | 4.2257033757492 | | 1996 | -2.553703585346 |
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