Year Percent 2000 6.64 2001 6.17 2002 6.13 2003 6.5 2004 6.19 2005 4.78 2006 3.56 2007 2.71 2008 3.01 2009 3.43 2010 2.8 2011 2.33 2012 2.32 2013 2.13 2014 2.15 2015 1.43 2016 1.34 2017 0.86