Year Number 2004 0.839443206787109 2005 0.442666381597519 2006 0.508818447589874 2007 0.483246594667435 2008 0.500850796699524 2009 -0.143221497535706 2010 0.339058101177216 2011 0.860623061656952 2012 0.67957615852356 2013 0.846709191799164 2014 1.16425490379333 2015 1.22000181674957 2016 0.975613653659821 2017 0.981489479541779 2018 0.955986976623535 2019 1.0513995885849 2020 1.00336503982544 2021 0.476192206144333 2022 0.563698709011078