Year Percent 2003-01-01 51.100 2004-01-01 51.175 2005-01-01 51.500 2006-01-01 51.800 2007-01-01 52.850 2008-01-01 53.575 2009-01-01 53.200 2010-01-01 53.175 2011-01-01 53.025 2012-01-01 53.125 2013-01-01 53.125 2014-01-01 52.850 2015-01-01 52.850 2016-01-01 52.775 2017-01-01 52.825