Year Number 1996 0.942838490009308 1998 0.883640766143799 2000 0.574339628219604 2002 0.449922442436218 2003 1.08701109886169 2004 0.893403232097626 2005 0.871916949748993 2006 0.854816734790802 2007 0.928755760192871 2008 0.912390053272247 2009 0.937309503555298 2010 0.938382148742676 2011 0.854587376117706 2012 0.953947246074677 2013 0.912419855594635 2014 1.30612897872925 2015 0.989677846431732 2016 1.09102046489716 2017 1.52906262874603 2018 1.59051811695099 2019 1.57226634025574 2020 1.61823654174805 2021 1.50712108612061 2022 1.51425933837891