Year Number 1996 0.125683024525642 1998 0.32502093911171 2000 0.640210628509521 2002 0.410248696804047 2003 0.29903855919838 2004 0.408170908689499 2005 0.325625747442245 2006 0.220006227493286 2007 0.30284458398819 2008 0.261874705553055 2009 0.140438765287399 2010 0.299279242753983 2011 0.384890913963318 2012 0.293291419744492 2013 0.330102741718292 2014 0.149542808532715 2015 0.0152472918853164 2016 -0.110105983912945 2017 -0.105891399085522 2018 -0.257414042949677 2019 -0.0751413851976395 2020 -0.0658019334077835 2021 -0.0757728293538094 2022 0.0698951333761215