| Year | Value | | 2021 | 11.205989388721 | | 2020 | 10.900321861404 | | 2019 | 11.20773850798 | | 2018 | 11.583919042128 | | 2017 | 11.582252173352 | | 2016 | 11.457765812549 | | 2015 | 11.661976257046 | | 2014 | 11.813825145938 | | 2013 | 12.125363537924 | | 2012 | 12.271105952448 | | 2011 | 12.384151272874 | | 2010 | 12.09761604251 | | 2009 | 11.729053776674 | | 2008 | 12.349798135975 | | 2007 | 12.162894724293 | | 2006 | 11.657447231064 | | 2005 | 11.104759393168 |
|