Year Number 1996 0.809140563011169 1998 0.876508176326752 2000 0.839712262153625 2002 0.83394581079483 2003 -0.174448385834694 2004 0.0141295678913593 2005 0.55942964553833 2006 0.619174003601074 2007 0.503692030906677 2008 0.106922201812267 2009 -0.0706491693854332 2010 0.0998813360929489 2011 0.0107107488438487 2012 -0.023023433983326 2013 0.017451100051403 2014 -0.160119161009789 2015 -0.218955487012863 2016 0.30263563990593 2017 0.309286713600159 2018 0.426162242889404 2019 0.498170644044876 2020 0.494029402732849 2021 0.429098635911942 2022 0.594402670860291