Year Number 2007 -0.356638461351395 2008 -0.328292846679688 2009 -0.399734556674957 2010 0.00997711718082428 2011 -0.0478462427854538 2012 -0.0245511252433062 2013 -0.649806022644043 2014 -0.478502005338669 2015 0.515011131763458 2016 0.581183969974518 2017 0.561119318008423 2018 0.509996652603149 2019 0.529517710208893 2020 0.599186837673187 2021 0.604154706001282 2022 0.601521968841553