Year Number 1996 -0.203850328922272 1998 -0.367153853178024 2000 -0.423614680767059 2002 -0.517882883548737 2003 -0.575900852680206 2004 -0.619943141937256 2005 -0.663847804069519 2006 -0.564467251300812 2007 -0.4570552110672 2008 -0.580651640892029 2009 -0.555844962596893 2010 -0.477120876312256 2011 -0.510029077529907 2012 -0.518265724182129 2013 -0.524389088153839 2014 -0.614730000495911 2015 -0.541154861450195 2016 -0.31358602643013 2017 -0.29889103770256 2018 -0.383601844310761 2019 -0.445426762104034 2020 -0.434385359287262 2021 -0.416192442178726 2022 -0.313648909330368