| Year | Value | | 2022 | 6.322 | | 2021 | 7.719 | | 2020 | 8.627 | | 2019 | 6.331 | | 2018 | 6.427 | | 2017 | 6.752 | | 2016 | 6.814 | | 2015 | 7.41 | | 2014 | 7.467 | | 2013 | 7.322 | | 2012 | 7.472 | | 2011 | 7.47 | | 2010 | 7.654 | | 2009 | 7.257 | | 2008 | 7.17 | | 2007 | 8.475 | | 2006 | 9.04 | | 2005 | 9.524 | | 2004 | 8.337 | | 2003 | 5.904 | | 2002 | 8.205 | | 2001 | 9.14 | | 1995 | 9.59 |
|