Year Number 1996 0.878931701183319 1998 1.18025457859039 2000 0.663586676120758 2002 0.940030038356781 2003 0.947933495044708 2004 0.593536019325256 2005 0.898072719573975 2006 0.784178674221039 2007 1.03668713569641 2008 1.0821361541748 2009 0.920496821403503 2010 1.05331683158875 2011 0.974757313728333 2012 1.08840095996857 2013 1.11951816082001 2014 1.03912115097046 2015 0.865759432315826 2016 0.708230555057526 2017 0.902730107307434 2018 0.736512184143066 2019 0.667275547981262 2020 0.633921086788177 2021 0.617806434631348 2022 0.44343426823616