Year Percent 2001-01-01 41.600 2002-01-01 41.525 2003-01-01 41.600 2004-01-01 41.725 2005-01-01 41.250 2006-01-01 40.750 2007-01-01 40.325 2008-01-01 40.200 2009-01-01 40.625 2010-01-01 41.050 2011-01-01 40.325 2012-01-01 39.925 2013-01-01 39.525 2014-01-01 39.125 2015-01-01 38.675 2016-01-01 38.525 2017-01-01 37.950