Year Number 1996 0.371830761432648 1998 -0.191821798682213 2000 -0.577913403511047 2002 -0.103369668126106 2003 -1.23235356807709 2004 -0.611157953739166 2005 -0.49144771695137 2006 -0.0852985605597496 2007 -0.176476791501045 2008 0.01727613247931 2009 -0.15804822742939 2010 -0.282062977552414 2011 -0.058007225394249 2012 0.0337390303611755 2013 0.0674438998103142 2014 0.498692989349365 2015 0.53887152671814 2016 0.524906516075134 2017 0.394011855125427 2018 0.407829284667969 2019 0.530268251895905 2020 0.693885385990143 2021 0.712418019771576 2022 0.802727520465851