| Year | Value | | 2021 | 8.4443766198584 | | 2020 | -5.5312133829866 | | 2019 | 1.4499982902552 | | 2018 | 0.5653814749995 | | 2017 | 0.63281597352355 | | 2016 | -1.4297139834284 | | 2015 | 3.8395759401286 | | 2014 | 0.25264012228166 | | 2013 | 0.42953446577003 | | 2012 | 3.5696988385407 | | 2011 | -3.4794413777363 | | 2010 | 9.8975695877485 | | 2009 | 7.8183141005163 | | 2008 | -7.3163397761539 | | 2007 | -4.1804152001538 | | 2006 | 3.3506804940649 | | 2005 | 5.3425843159169 | | 2004 | 2.0977974697609 | | 2003 | 5.0798453704711 | | 2002 | -1.4285867669383 | | 2001 | -2.3624343273829 | | 2000 | 4.1141566161805 | | 1999 | 2.0033314615152 | | 1998 | 4.0636016727963 | | 1997 | 3.8329021223373 | | 1996 | 0.69230816036001 |
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