Year Percent 2005-01-01 48.475 2006-01-01 49.500 2007-01-01 50.550 2008-01-01 51.250 2009-01-01 50.825 2010-01-01 50.725 2011-01-01 51.025 2012-01-01 50.950 2013-01-01 50.850 2014-01-01 51.225 2015-01-01 51.750 2016-01-01 52.575 2017-01-01 53.275