Year Percent 2002 46.5306 2003 44.30263 2004 44.51905 2005 44.47885 2006 45.83757 2007 46.08474 2008 46.68092 2009 46.21523 2010 46.0063 2011 47.39884 2012 48.10529 2013 48.83217 2014 49.01694 2015 50.25095 2016 49.96833 2017 49.3019