Year Percent 1992 1.2128 1993 1.21353 1994 1.29166 1995 3.16547 1996 2.71802 1997 2.58481 1998 2.08926 1999 2.00815 2000 2.04053 2001 2.05613 2002 2.0714 2003 1.94957 2004 1.96884 2005 1.99237 2006 2.00301 2007 2.05099 2008 2.02761 2009 1.97733 2010 1.95295 2011 1.91682 2012 1.87989 2013 1.85061 2014 1.8085 2015 1.77124 2016 1.7228 2017 1.69368 2018 1.66378 2019 1.65162 2020 1.58748