Year Number 1996 -2.11674880981445 1998 -1.84154975414276 2000 -1.64776349067688 2002 -0.982307970523834 2003 -1.09949171543121 2004 -1.30745339393616 2005 -1.39246213436127 2006 -1.3861448764801 2007 -0.752052187919617 2008 -0.830599308013916 2009 -1.02539455890656 2010 -1.03453838825226 2011 -1.02323389053345 2012 -1.24085974693298 2013 -1.18237400054932 2014 -0.69334077835083 2015 -0.882318019866943 2016 -0.78061830997467 2017 -0.674310863018036 2018 -0.74773895740509 2019 -0.512072920799255 2020 -0.500084042549133 2021 -0.676817953586578 2022 -0.694840013980865