Year Percent 2005-01-01 54.775 2006-01-01 53.675 2007-01-01 52.975 2008-01-01 52.125 2009-01-01 51.100 2010-01-01 50.425 2011-01-01 49.375 2012-01-01 47.500 2013-01-01 45.700 2014-01-01 44.125 2015-01-01 42.750 2016-01-01 40.925 2017-01-01 39.425