Year Number 1996 1.10043299198151 1998 1.1276113986969 2000 1.11232662200928 2002 1.01157546043396 2003 0.963035404682159 2004 0.871200382709503 2005 0.976367771625519 2006 1.14037656784058 2007 1.12200117111206 2008 1.15002512931824 2009 0.857001900672913 2010 0.838140785694122 2011 0.719682574272156 2012 0.685145795345306 2013 0.680240392684937 2014 0.776729643344879 2015 0.403735220432281 2016 0.410313665866852 2017 0.492237210273743 2018 0.472064346075058 2019 0.468620896339417 2020 0.49604406952858 2021 0.501065075397491 2022 0.442538172006607