Year Percent 1990 6.80105 1991 6.79265 1992 4.01054 1993 4.04013 1994 3.21466 1995 2.83136 1996 2.69158 1997 1.77584 1998 1.76619 1999 2.0229 2000 1.84703 2001 1.57005 2002 1.55764 2003 1.54169 2004 1.57545 2005 1.57062 2006 1.54548 2007 1.52802 2008 1.51613 2009 1.46658 2010 1.47802 2011 1.45816 2012 1.45 2013 1.44177 2014 1.43556 2015 1.42604 2016 1.42171 2017 1.4262 2018 1.42178 2019 1.42121 2020 1.53898