Year Percent 2003-01-01 70.300 2004-01-01 73.600 2005-01-01 74.500 2006-01-01 75.000 2007-01-01 77.700 2008-01-01 72.875 2009-01-01 70.600 2010-01-01 77.350 2011-01-01 76.625 2012-01-01 75.375 2013-01-01 78.225 2014-01-01 77.000 2015-01-01 65.850 2016-01-01 68.950 2017-01-01 71.725