Year Number 1996 0.440209209918976 1998 0.599269092082977 2000 0.212451234459877 2002 0.492683351039886 2003 0.483302503824234 2004 0.30226343870163 2005 0.233044505119324 2006 -0.0139150014147162 2007 -0.0173227712512016 2008 0.0996380820870399 2009 0.147267401218414 2010 0.0824754610657692 2011 0.119975283741951 2012 0.0793254524469376 2013 0.132779225707054 2014 0.249270841479301 2015 0.249509304761887 2016 0.152817890048027 2017 0.119800709187984 2018 0.0581610128283501 2019 0.0876266658306122 2020 0.418793022632599 2021 0.348301738500595 2022 0.39629203081131