Year Percent 2003-01-01 74.925 2004-01-01 73.500 2005-01-01 75.150 2006-01-01 75.375 2007-01-01 76.000 2008-01-01 75.025 2009-01-01 72.075 2010-01-01 71.600 2011-01-01 71.675 2012-01-01 72.700 2013-01-01 73.700 2014-01-01 74.875 2015-01-01 76.425 2016-01-01 77.325 2017-01-01 76.750