Year Percent 2005-01-01 83.675 2006-01-01 84.825 2007-01-01 86.425 2008-01-01 87.025 2009-01-01 86.100 2010-01-01 86.775 2011-01-01 87.975 2012-01-01 88.375 2013-01-01 88.175 2014-01-01 88.050 2015-01-01 88.150 2016-01-01 88.050 2017-01-01 88.325