Year Percent 2000-01-01 51.2319644294118 2001-01-01 50.6453584085464 2002-01-01 50.1403956363972 2003-01-01 50.9374691811382 2004-01-01 49.8610550274688 2005-01-01 49.7343428329116 2006-01-01 49.4994217219692 2007-01-01 49.5448425382061 2008-01-01 49.8047100706405 2009-01-01 50.7005496028160 2010-01-01 50.4245057084576 2011-01-01 50.1890133804649 2012-01-01 49.8809054658407 2013-01-01 49.6561943407342 2014-01-01 48.5089613962931 2015-01-01 48.1084577905960 2016-01-01 47.8381119481612 2017-01-01 47.3447999454946