Year Percent 1990 2.09422 1991 1.95367 1992 2.01123 1993 1.9346 1994 1.88913 1995 2.55183 1996 2.52157 1997 2.51479 1998 2.3813 1999 2.22539 2000 2.14146 2001 2.04507 2002 1.97372 2003 1.87582 2004 1.80846 2005 1.82018 2006 1.79524 2007 1.78149 2008 1.75688 2009 1.32836 2010 1.46407 2011 1.49609 2012 1.43073 2013 1.42164 2014 1.38907 2015 1.39099 2016 1.37607 2017 1.32933 2018 1.30522 2019 1.32008 2020 1.3452