Year Number 1996 0.468430697917938 1998 0.309278875589371 2000 0.262206673622131 2002 0.306561231613159 2003 0.211418956518173 2004 0.212290197610855 2005 0.149778127670288 2006 0.0309586375951767 2007 0.211472004652023 2008 0.270571917295456 2009 0.32113441824913 2010 0.298928886651993 2011 0.283398628234863 2012 0.47439906001091 2013 0.456511080265045 2014 0.363258302211761 2015 0.306994050741196 2016 0.284244060516357 2017 0.222507447004318 2018 0.352696746587753 2019 0.347733318805695 2020 0.196720212697983 2021 0.224117517471313 2022 0.0532664284110069