Year Percent 2006-01-01 57.425 2007-01-01 57.525 2008-01-01 58.250 2009-01-01 59.425 2010-01-01 61.075 2011-01-01 62.300 2012-01-01 62.825 2013-01-01 63.975 2014-01-01 64.425 2015-01-01 65.450 2016-01-01 66.475 2017-01-01 67.525