Year Percent 2000 2.51476 2001 2.03024 2002 2.17709 2003 2.04805 2004 2.83404 2005 2.37142 2006 2.11221 2007 2.00327 2008 1.95744 2009 2.29635 2010 2.48266 2011 2.34833 2012 2.31757 2013 2.43277 2014 2.28234 2015 2.00451 2016 1.47024 2017 1.67797