Year Percent 2005-01-01 71.625 2006-01-01 72.400 2007-01-01 73.225 2008-01-01 73.175 2009-01-01 70.850 2010-01-01 70.200 2011-01-01 70.075 2012-01-01 69.300 2013-01-01 68.725 2014-01-01 68.925 2015-01-01 69.600 2016-01-01 70.575 2017-01-01 71.550