Year Percent 2005-01-01 33.850 2006-01-01 33.675 2007-01-01 33.750 2008-01-01 33.700 2009-01-01 33.800 2010-01-01 33.925 2011-01-01 33.450 2012-01-01 33.550 2013-01-01 33.600 2014-01-01 33.675 2015-01-01 34.150 2016-01-01 33.425 2017-01-01 33.300