| Year | Value | | 2021 | 10.734378819693 | | 2020 | 10.451788673741 | | 2019 | 10.741378172698 | | 2018 | 11.131522292929 | | 2017 | 11.207068196001 | | 2016 | 11.083548056883 | | 2015 | 11.362661838311 | | 2014 | 11.633241113103 | | 2013 | 11.912108707564 | | 2012 | 12.067194011059 | | 2011 | 12.233594577192 | | 2010 | 11.912000409096 | | 2009 | 11.624456236995 | | 2008 | 12.053094362569 | | 2007 | 11.596234366273 | | 2006 | 11.04598132262 | | 2005 | 10.628300049749 |
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