Year Percent 2000-01-01 42.1801189232611 2001-01-01 41.5704380606845 2002-01-01 40.9255228658901 2003-01-01 41.5608335861872 2004-01-01 40.2175654106782 2005-01-01 39.6054172354634 2006-01-01 38.4524117111411 2007-01-01 37.9773834893378 2008-01-01 37.6985140064568 2009-01-01 38.4567280990781 2010-01-01 37.8266876679262 2011-01-01 37.2631725252855 2012-01-01 37.1558082881431 2013-01-01 36.6040786956303 2014-01-01 35.2469938655787 2015-01-01 34.6209625367537 2016-01-01 34.0552137600604 2017-01-01 33.3592188354830