Year Number 1996 1.79586124420166 1998 1.75143575668335 2000 1.8001868724823 2002 1.84246826171875 2003 1.88671100139618 2004 1.87256228923798 2005 1.79775130748749 2006 1.85117638111115 2007 1.89182782173157 2008 1.91915678977966 2009 1.9582816362381 2010 1.93030881881714 2011 1.91803658008575 2012 1.92827761173248 2013 1.95055162906647 2014 1.97517240047455 2015 1.99026310443878 2016 1.9524188041687 2017 1.81789696216583 2018 1.78393721580505 2019 1.79192125797272 2020 1.76685619354248 2021 1.70026206970215 2022 1.69006848335266