Year Number 1996 1.34199249744415 1998 1.31633019447327 2000 1.36238181591034 2002 1.32036375999451 2003 1.18837487697601 2004 1.50002658367157 2005 1.25225210189819 2006 1.25449228286743 2007 1.24336647987366 2008 1.16264343261719 2009 1.07115530967712 2010 1.23648881912231 2011 1.37673103809357 2012 1.36136555671692 2013 1.45392656326294 2014 1.46792757511139 2015 1.51113760471344 2016 1.50114333629608 2017 1.56213212013245 2018 1.51216089725494 2019 1.41574943065643 2020 1.46777844429016 2021 1.3952362537384 2022 1.31238234043121