Year Percent 2000-01-01 57.600 2001-01-01 57.875 2002-01-01 58.175 2003-01-01 58.325 2004-01-01 58.625 2005-01-01 59.000 2006-01-01 59.100 2007-01-01 58.825 2008-01-01 59.100 2009-01-01 58.425 2010-01-01 58.050 2011-01-01 57.950 2012-01-01 58.100 2013-01-01 58.725 2014-01-01 59.750 2015-01-01 60.400 2016-01-01 61.025 2017-01-01 61.725