Year Percent 2000 20.27898 2001 19.78833 2002 20.04152 2003 19.37685 2004 20.55692 2005 21.05815 2006 19.71786 2007 19.10707 2008 20.95113 2009 21.23265 2010 19.53787 2011 19.68944 2012 19.08144 2013 20.24086 2014 20.41683