Year Number 1996 0.960634410381317 1998 0.957083582878113 2000 0.970597624778748 2002 0.948852479457855 2003 0.703260600566864 2004 0.78897613286972 2005 0.585461497306824 2006 0.518689930438995 2007 0.575748801231384 2008 0.537432789802551 2009 0.761055648326874 2010 0.760903239250183 2011 0.726528644561768 2012 0.793113589286804 2013 0.667774379253387 2014 0.766151249408722 2015 0.716790080070496 2016 0.629420042037964 2017 0.59318733215332 2018 0.556203603744507 2019 0.558157503604889 2020 0.604394853115082 2021 0.575343668460846 2022 0.533023357391357