Year Number 2002 1.2750111161 2003 1.3608587944 2004 1.3492028203 2005 1.3682589087 2006 1.4103093438 2007 1.4472463952 2008 1.4742107603 2009 1.5335704758 2010 1.5006669631 2011 1.4937750111 2012 1.4695420187 2013 1.5671409515 2014 1.5371276123 2015 1.5195642508 2016 1.4804357492 2017 1.4959982214 2018 1.4962205425 2019 1.4895509115 2020 1.4784348599