Year Percent 2005-01-01 70.625 2006-01-01 70.975 2007-01-01 71.050 2008-01-01 71.250 2009-01-01 71.300 2010-01-01 71.600 2011-01-01 72.475 2012-01-01 72.650 2013-01-01 72.975 2014-01-01 73.200 2015-01-01 73.075 2016-01-01 73.700 2017-01-01 74.000