Year Number 2004 0.319958239793777 2005 0.213636070489883 2006 0.305708646774292 2007 0.366895705461502 2008 0.381994009017944 2009 0.412385046482086 2010 0.460222959518433 2011 0.462991625070572 2012 0.502660512924194 2013 0.499141931533813 2014 0.506450057029724 2015 0.462172716856003 2016 0.486370205879211 2017 0.469926714897156 2018 0.486478626728058 2019 0.486127644777298 2020 0.516059041023254 2021 0.487263292074203 2022 0.473354339599609