Year Number 1996 0.703103303909302 1998 0.673875689506531 2000 0.687808454036713 2002 0.708452701568604 2003 0.724850833415985 2004 0.72966194152832 2005 0.54195910692215 2006 0.550342977046967 2007 0.657145261764526 2008 0.610481977462769 2009 0.571816921234131 2010 0.53067022562027 2011 0.300949603319168 2012 0.310884863138199 2013 0.32428964972496 2014 0.360036998987198 2015 0.295811653137207 2016 0.321833670139313 2017 0.323024958372116 2018 0.323131740093231 2019 0.322351813316345 2020 0.357103317975998 2021 0.363453030586243 2022 0.338811218738556