Year Number 1996 -0.48242661356926 1998 -0.402721375226974 2000 -0.345562547445297 2002 -0.67900162935257 2003 -0.636823534965515 2004 -0.604071080684662 2005 -0.317553699016571 2006 -0.518898844718933 2007 -0.490206182003021 2008 -0.464453905820847 2009 -0.531529664993286 2010 -0.581304907798767 2011 -0.541880786418915 2012 -0.55492377281189 2013 -0.515489280223846 2014 -0.360538631677628 2015 -0.356080949306488 2016 0.0651851072907448 2017 0.0404918380081654 2018 -0.0353447571396828 2019 -0.0502180941402912 2020 -0.188712939620018 2021 -0.171954914927483 2022 -0.158443406224251