Year Percent 1991 2.16388 1992 2.10939 1993 2.0474 1994 2.08031 1995 2.05358 1996 1.94853 1997 1.85419 1998 1.71808 1999 1.55393 2000 1.53455 2001 1.39226 2002 1.38574 2003 1.2488 2004 1.27649 2005 1.37677 2006 1.35242 2007 1.36604 2008 1.08091 2009 1.11045 2010 1.21589 2011 1.22021 2012 1.18889 2013 1.05876 2014 1.25617 2015 1.13849 2016 1.12564 2017 1.16303 2018 1.07004 2019 1.0454