Year Percent 1990 3.28774 1991 3.17498 1992 2.55482 1993 2.49423 1994 1.98977 1995 1.72694 1996 1.68582 1997 1.49735 1998 1.38077 1999 1.34779 2000 1.33681 2001 1.29377 2002 1.27414 2003 1.25585 2005 1.13207 2006 1.09496 2007 1.06019 2008 1.0305 2009 1.00273 2010 1.03551 2011 1.01887 2012 1.00616 2013 0.98285 2014 0.97095 2015 0.95773 2016 0.95468 2017 0.94911 2018 0.94486 2019 0.93418 2020 0.95339