| Year | Value | | 2021 | 0.66171003717472 | | 2020 | 0.67657992565056 | | 2019 | 0.66914498141264 | | 2018 | 0.68401486988848 | | 2017 | 0.68401486988848 | | 2016 | 0.66914498141264 | | 2015 | 0.64684014869888 | | 2014 | 0.64907063197026 | | 2013 | 0.57992565055762 | | 2012 | 12.788104089219 | | 2011 | 12.862453531599 | | 2010 | 12.788104089219 | | 2009 | 12.862453531599 | | 2008 | 12.862453531599 | | 2007 | 12.936802973978 | | 2006 | 12.936802973978 |
|