Year Number 1996 0.644221544265747 1998 0.710790991783142 2000 0.848681509494781 2002 0.976482391357422 2003 0.931504726409912 2004 0.947524964809418 2005 0.89995676279068 2006 0.93112325668335 2007 0.947436213493347 2008 0.935453057289124 2009 0.876306593418121 2010 0.910946249961853 2011 0.965979039669037 2012 0.973016917705536 2013 0.959550261497498 2014 0.959610283374786 2015 0.965451538562775 2016 0.961433291435242 2017 0.912065982818604 2018 0.847073376178741 2019 0.86135721206665 2020 0.879936933517456 2021 0.904963314533234 2022 0.886331796646118