Year Number 2005 -0.316166281700134 2006 -0.646908700466156 2007 -0.822250843048096 2008 -0.764792680740356 2009 -0.689701557159424 2010 -0.716677844524384 2011 -0.306141883134842 2012 -0.224154844880104 2013 -0.000668602180667222 2014 -0.0144994370639324 2015 0.648119211196899 2016 0.706911265850067 2017 0.775618433952332 2018 0.348221093416214 2019 0.367132216691971 2020 0.46734556555748 2021 0.416723072528839 2022 0.385005086660385