Year Percent 1990 2.35202 1991 2.97353 1992 2.46057 1993 2.38774 1994 2.171 1995 2.1363 1996 1.80005 1997 2.05029 1998 2.03559 1999 1.94437 2000 1.73125 2001 2.06938 2002 1.50978 2003 1.72082 2004 1.50541 2005 1.45078 2006 1.30297 2007 1.33517 2008 1.2866 2009 1.23997 2010 1.19465 2011 1.14969 2012 1.10714 2013 1.06669 2014 1.02835 2015 0.99194 2016 0.95644 2017 0.92205 2018 0.8895 2019 0.85841 2020 0.83696