Year Percent 1990 4.05193 1991 3.95649 1992 3.5098 1993 3.38605 1994 2.08367 1995 2.66181 1996 2.62104 1997 2.54536 1998 2.48896 1999 2.44763 2000 2.39101 2001 2.83554 2002 2.76746 2003 3.39487 2004 2.10086 2005 2.05222 2006 2.00363 2007 1.95483 2008 1.27052 2009 1.33219 2010 1.29675 2011 1.25914 2012 1.22357 2013 1.18871 2014 1.15491 2015 0.77415 2016 0.75186 2017 0.65634 2018 0.70905 2019 0.61904 2020 0.60663