Year Percent 2000 12.65711 2001 14.70722 2002 16.05666 2003 16.5849 2004 17.20666 2005 16.48779 2006 18.1699 2007 19.51182 2008 18.73907 2009 17.34652 2010 18.52559 2011 17.88094 2012 18.47289 2013 17.23874 2014 16.54203