Year Percent 1990 0.73734 1991 0.71902 1992 0.69823 1993 0.67882 1994 0.66191 1995 1.16281 1996 1.28404 1997 1.52304 1998 1.56011 1999 1.52693 2000 1.49533 2001 1.40246 2002 1.45705 2003 1.621 2004 2.02942 2005 2.00106 2006 1.97228 2007 1.94729 2008 1.92409 2009 2.29018 2010 2.2636 2011 2.24149 2012 2.22319 2013 2.2062 2014 2.18677 2015 2.17333 2016 2.12632 2017 1.46525 2018 1.42541 2019 1.39694 2020 1.3718