Year Number 1996 -1.2748167514801 1998 -0.91581529378891 2000 -1.06467461585999 2002 -0.670977175235748 2003 -0.489668667316437 2004 -0.67443460226059 2005 -1.01584625244141 2006 -0.896951019763947 2007 -0.891591012477875 2008 -0.865504682064056 2009 -1.01221060752869 2010 -1.07546448707581 2011 -1.21547913551331 2012 -1.28747808933258 2013 -1.25735402107239 2014 -1.26760983467102 2015 -1.45967710018158 2016 -1.26049017906189 2017 -0.622010767459869 2018 -0.21528185904026 2019 -0.249232843518257 2020 -0.199700385332108 2021 -0.105402499437332 2022 -0.0414298065006733