| Year | Value | | 2021 | 11.196189049109 | | 2020 | 10.884558945594 | | 2019 | 11.188669272796 | | 2018 | 11.594161195422 | | 2017 | 11.590932446254 | | 2016 | 11.46773429476 | | 2015 | 11.666026691995 | | 2014 | 11.830185342929 | | 2013 | 12.171416557032 | | 2012 | 12.313324878311 | | 2011 | 12.432145210748 | | 2010 | 12.147260474041 | | 2009 | 11.789930886503 | | 2008 | 12.401792974312 | | 2007 | 12.222059549411 | | 2006 | 11.7038839795 | | 2005 | 11.131064022823 |
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