Year Percent 2003-01-01 51.725 2004-01-01 51.525 2005-01-01 51.450 2006-01-01 51.400 2007-01-01 51.950 2008-01-01 52.375 2009-01-01 51.650 2010-01-01 51.500 2011-01-01 51.300 2012-01-01 51.175 2013-01-01 50.825 2014-01-01 50.325 2015-01-01 50.275 2016-01-01 50.300 2017-01-01 50.525