Year Number 1996 -0.718783438205719 1998 -1.06540274620056 2000 -1.05687987804413 2002 -0.571163654327393 2003 -0.590705573558807 2004 -0.561549425125122 2005 -0.743174850940704 2006 -0.903966546058655 2007 -0.856526553630829 2008 -0.868917524814606 2009 -0.790999948978424 2010 -0.965909421443939 2011 -1.21731686592102 2012 -1.31802463531494 2013 -1.31746447086334 2014 -1.31105923652649 2015 -1.31306099891663 2016 -1.37202835083008 2017 -1.38725745677948 2018 -1.41806530952454 2019 -1.42869198322296 2020 -1.4533017873764 2021 -1.49894762039185 2022 -1.41756176948547