Year Number 1996 0.525695502758026 1998 0.319004893302917 2000 0.408773571252823 2002 0.353681147098541 2003 0.126424372196198 2004 0.150153517723083 2005 0.484037667512894 2006 0.405120253562927 2007 0.251871973276138 2008 0.165260821580887 2009 0.271775960922241 2010 0.148407876491547 2011 0.189088448882103 2012 0.267358660697937 2013 0.25057727098465 2014 -0.0223473571240902 2015 0.0638082250952721 2016 0.226832523941994 2017 0.211421594023705 2018 0.0327426008880138 2019 0.0389102399349213 2020 -0.0385358110070229 2021 -0.118189707398415 2022 -0.0305646620690823