Year Percent 1991 1.085 1992 1.136 1993 1.08 1994 1.155 1995 1.23 1996 1.164 1997 1.058 1998 0.922 1999 0.758 2000 0.774 2001 0.681 2002 0.691 2003 0.583 2004 0.595 2005 0.728 2006 0.668 2007 0.747 2008 0.727 2009 0.553 2010 0.605 2011 0.657 2012 0.686 2013 0.601 2014 0.712 2015 0.645 2016 0.625 2017 0.613 2018 0.598 2019 0.583 2020 0.568 2021 0.552 2022 0.537