Year Percent 2005-01-01 59.825 2006-01-01 60.450 2007-01-01 61.000 2008-01-01 61.125 2009-01-01 59.225 2010-01-01 58.625 2011-01-01 58.425 2012-01-01 57.950 2013-01-01 57.500 2014-01-01 57.850 2015-01-01 58.275 2016-01-01 58.975 2017-01-01 59.650