| Year | Value | | 2021 | 10.888210841805 | | 2020 | 10.634964836816 | | 2019 | 10.934945850218 | | 2018 | 11.34040853301 | | 2017 | 11.341100887893 | | 2016 | 11.199513592178 | | 2015 | 11.421884165489 | | 2014 | 11.593133878911 | | 2013 | 11.907218419815 | | 2012 | 12.041153304978 | | 2011 | 12.14405369289 | | 2010 | 11.868543032713 | | 2009 | 11.515701768785 | | 2008 | 12.052267497554 | | 2007 | 11.779881768727 | | 2006 | 11.267694101858 | | 2005 | 10.735530657462 |
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