Year Number 1996 1.19231188297272 1998 1.06593120098114 2000 1.22991895675659 2002 0.936939835548401 2003 1.16987371444702 2004 1.20001101493835 2005 1.2101241350174 2006 1.3208487033844 2007 1.23022782802582 2008 1.32388854026794 2009 1.36922454833984 2010 1.55362319946289 2011 1.55437541007996 2012 1.61894869804382 2013 1.64827847480774 2014 1.69047617912292 2015 1.53004574775696 2016 1.48238265514374 2017 1.4809068441391 2018 1.38864803314209 2019 1.43116724491119 2020 1.46393418312073 2021 1.53605020046234 2022 1.53997182846069