Year Number 1996 0.466799110174179 1998 0.638839483261108 2000 0.454958707094193 2002 0.506276667118073 2003 -0.145084381103516 2004 -0.717405676841736 2005 -0.870126605033875 2006 -1.13020014762878 2007 -1.11284792423248 2008 -1.27209329605103 2009 -1.42447113990784 2010 -1.44278836250305 2011 -1.13353371620178 2012 -1.21663069725037 2013 -1.31168270111084 2014 -0.906386315822601 2015 -0.995044946670532 2016 -0.991300225257874 2017 -0.754879355430603 2018 -0.799434542655945 2019 -0.49142050743103 2020 -0.578276574611664 2021 -0.568726181983948 2022 -0.383099317550659