Year Percent 2005-01-01 39.3043409742132 2006-01-01 40.4659086639893 2007-01-01 40.7400890758630 2008-01-01 40.5652412610303 2009-01-01 40.4686338937212 2010-01-01 40.3115040869888 2011-01-01 40.6358721018679 2012-01-01 41.6973022068665 2013-01-01 41.6936499584160 2014-01-01 40.9552150619787 2015-01-01 41.4117703095080 2016-01-01 41.6898305703797 2017-01-01 41.4030041412412