| Year | Value | | 2022 | 1.1070851956966 | | 2021 | 1.0831216171435 | | 2020 | 1.7816901408451 | | 2019 | 1.6957507640737 | | 2018 | 1.3178591981584 | | 2017 | 1.5944099768127 | | 2016 | 1.5883315158124 | | 2015 | 2.3180506773708 | | 2014 | 2.0468458508948 | | 2013 | 2.2703690433536 | | 2012 | 2.8772836952775 | | 2011 | 1.9694934765925 | | 2010 | 2.9926287139941 | | 2009 | 5.0187095886642 | | 2008 | 3.647031611411 | | 2007 | 4.3726971260133 | | 2006 | 3.7692816218599 | | 2005 | 1.7802292883409 |
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