Year Percent 2005-01-01 51.100 2006-01-01 52.475 2007-01-01 53.700 2008-01-01 54.550 2009-01-01 55.225 2010-01-01 56.175 2011-01-01 58.000 2012-01-01 58.475 2013-01-01 59.550 2014-01-01 60.225 2015-01-01 60.750 2016-01-01 62.000 2017-01-01 62.725