Year Percent 2006-01-01 25.050 2007-01-01 25.175 2008-01-01 26.150 2009-01-01 27.825 2010-01-01 29.625 2011-01-01 31.050 2012-01-01 31.775 2013-01-01 33.250 2014-01-01 33.550 2015-01-01 34.900 2016-01-01 36.175 2017-01-01 37.525