Year Number 1996 0.375723421573639 1998 0.416656792163849 2000 0.416736394166946 2002 0.522498726844788 2003 0.470419079065323 2004 0.417557060718536 2005 0.339725077152252 2006 0.67924028635025 2007 0.477556079626083 2008 0.306298166513443 2009 0.366235703229904 2010 0.158016294240952 2011 -0.00149573176167905 2012 -0.0522028878331184 2013 -0.0580974668264389 2014 -0.0655622854828835 2015 -0.101347163319588 2016 -0.205795958638191 2017 -0.050398975610733 2018 -0.00628353748470545 2019 -0.0353328697383404 2020 -0.188614159822464 2021 -0.210014835000038 2022 -0.299408107995987