Year Percent 2005-01-01 70.100 2006-01-01 70.900 2007-01-01 71.500 2008-01-01 72.300 2009-01-01 71.800 2010-01-01 70.075 2011-01-01 70.900 2012-01-01 70.925 2013-01-01 70.775 2014-01-01 71.125 2015-01-01 71.400 2016-01-01 71.825 2017-01-01 71.950