Year Number 1996 1.03555142879486 1998 1.11396324634552 2000 1.22359979152679 2002 1.16340851783752 2003 0.764638483524323 2004 0.624410927295685 2005 1.38492727279663 2006 1.34965407848358 2007 1.23301076889038 2008 1.18549370765686 2009 1.22989845275879 2010 1.27522957324982 2011 1.10943698883057 2012 1.20170080661774 2013 1.1603866815567 2014 0.636045277118683 2015 0.458486795425415 2016 0.489710420370102 2017 0.67628401517868 2018 0.802380979061127 2019 1.00210762023926 2020 0.88242495059967 2021 0.900379121303558 2022 0.949675500392914