Year Number 1996 0.226543545722961 1998 0.249043971300125 2000 0.217144221067429 2002 -0.0244121737778187 2003 0.0618866458535194 2004 -0.189794227480888 2005 -0.0545144379138947 2006 -0.0254304427653551 2007 -0.171447739005089 2008 -0.0302958749234676 2009 -0.0469018258154392 2010 0.29281359910965 2011 0.321024298667908 2012 0.336211621761322 2013 0.458545207977295 2014 0.663734495639801 2015 0.661673128604889 2016 0.642764985561371 2017 0.603064239025116 2018 0.654241681098938 2019 0.636282980442047 2020 0.689669668674469 2021 0.783069550991058 2022 0.839519560337067