Year Number 2004 -0.0281551741063595 2005 0.114489793777466 2006 -0.0318083874881268 2007 -0.533418953418732 2008 -0.510507524013519 2009 -0.356076508760452 2010 -0.469835221767426 2011 -0.803260207176209 2012 -0.643046975135803 2013 -0.568209290504456 2014 -0.515400052070618 2015 -0.160680666565895 2016 -0.0465805158019066 2017 0.416537791490555 2018 0.163868218660355 2019 0.0971257835626602 2020 0.358195006847382 2021 0.30223348736763 2022 0.379839152097702