| Year | Value | | 2022 | 1.1283072472789 | | 2021 | 0.84592881521209 | | 2020 | 1.0230373914584 | | 2019 | 0.83172717171946 | | 2018 | 0.8044205884425 | | 2017 | 0.80289972720665 | | 2016 | 0.77786814238886 | | 2015 | 0.79428030403161 | | 2014 | 0.75832926767435 | | 2013 | 0.72174071050535 | | 2012 | 0.70395373609102 | | 2011 | 0.80477594937542 | | 2010 | 0.72260702705787 | | 2009 | 0.48159727051354 | | 2008 | 0.016302794139236 |
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