Year Percent 2005-01-01 42.325 2006-01-01 43.450 2007-01-01 44.475 2008-01-01 45.475 2009-01-01 45.875 2010-01-01 46.225 2011-01-01 47.225 2012-01-01 48.700 2013-01-01 50.100 2014-01-01 51.775 2015-01-01 53.250 2016-01-01 55.225 2017-01-01 57.050