Year Number 1996 1.62955820560455 1998 1.55780613422394 2000 1.67868137359619 2002 1.50104343891144 2003 1.61011552810669 2004 1.65317785739899 2005 1.62860155105591 2006 1.49936544895172 2007 1.47794735431671 2008 1.47838854789734 2009 1.47848224639893 2010 1.50750553607941 2011 1.57907593250275 2012 1.61772203445435 2013 1.60607767105103 2014 1.52441298961639 2015 1.5548654794693 2016 1.5332738161087 2017 1.55807733535767 2018 1.60416686534882 2019 1.53711998462677 2020 1.59581446647644 2021 1.59364664554596 2022 1.63967132568359