| Year | Value | | 2021 | 2.0536167677391 | | 2020 | 2.5532455441463 | | 2019 | -1.8130799530295 | | 2018 | 0.56403049149348 | | 2017 | 0.35552088854683 | | 2016 | 1.9173109023338 | | 2015 | 0.57201574363425 | | 2014 | 2.1039852092504 | | 2013 | -1.488059084681 | | 2012 | -3.0458629277556 | | 2011 | 1.4974097987596 | | 2010 | -3.8995504065166 | | 2009 | 9.8164388450867 | | 2008 | 13.665399525244 | | 2007 | 3.5925213126643 |
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