Year Number 1996 1.115647315979 1998 0.930101573467255 2000 1.14111149311066 2002 1.2535662651062 2003 0.876536011695862 2004 1.0929559469223 2005 1.1533499956131 2006 1.24849283695221 2007 1.17421102523804 2008 1.34467613697052 2009 1.17959117889404 2010 1.16941487789154 2011 1.19142174720764 2012 1.36817455291748 2013 1.378178358078 2014 1.18627142906189 2015 1.29889214038849 2016 1.47746896743774 2017 1.59912312030792 2018 1.46800899505615 2019 1.4803055524826 2020 1.43841421604156 2021 1.44232499599457 2022 1.45994246006012