Year Number 1996 -0.526031970977783 1998 -0.0207697190344334 2000 0.0497975237667561 2002 -0.414172112941742 2003 -0.640924513339996 2004 -0.822401702404022 2005 -0.629358649253845 2006 -0.837807655334473 2007 -0.552382111549377 2008 -0.510431706905365 2009 -0.607227087020874 2010 -0.898418307304382 2011 -1.43705701828003 2012 -1.43632972240448 2013 -1.63883090019226 2014 -1.63117659091949 2015 -1.49933218955994 2016 -1.43972682952881 2017 -1.42964518070221 2018 -1.18810069561005 2019 -1.12460207939148 2020 -1.18191170692444 2021 -1.03284096717834 2022 -1.02805662155151