Year Percent 2006-01-01 25.475 2007-01-01 25.600 2008-01-01 26.450 2009-01-01 27.625 2010-01-01 30.100 2011-01-01 32.150 2012-01-01 33.675 2013-01-01 34.800 2014-01-01 34.550 2015-01-01 35.675 2016-01-01 36.675 2017-01-01 38.300