Year Percent 2000-01-01 72.275 2001-01-01 71.625 2002-01-01 71.650 2003-01-01 72.525 2004-01-01 72.175 2005-01-01 72.125 2006-01-01 74.000 2007-01-01 74.625 2008-01-01 75.000 2009-01-01 73.900 2010-01-01 73.525 2011-01-01 73.900 2012-01-01 75.925 2013-01-01 75.950 2014-01-01 76.975 2015-01-01 76.900 2016-01-01 77.725 2017-01-01 76.975