Year Percent 2004-01-01 51.6883 2005-01-01 46.4670 2006-01-01 49.8882 2007-01-01 49.7455 2008-01-01 51.7393 2009-01-01 60.5774 2010-01-01 55.7416 2011-01-01 53.7570 2012-01-01 51.9667 2013-01-01 49.9211 2014-01-01 53.6315 2015-01-01 54.9114 2016-01-01 48.9632