Year Number 1996 1.16952216625214 1998 1.18287515640259 2000 1.16698145866394 2002 1.28276693820953 2003 1.46513116359711 2004 1.51525795459747 2005 1.38492727279663 2006 1.34965407848358 2007 1.34201574325562 2008 1.33847212791443 2009 1.55316376686096 2010 1.54408740997314 2011 1.49057960510254 2012 1.38919961452484 2013 1.39717161655426 2014 1.45886182785034 2015 1.43777513504028 2016 1.45326995849609 2017 1.45908296108246 2018 1.45358550548553 2019 1.59749317169189 2020 1.66911089420319 2021 1.59549152851105 2022 1.64433610439301