Year Percent 1999-01-01 68.525 2000-01-01 68.300 2001-01-01 68.550 2002-01-01 68.100 2003-01-01 67.925 2004-01-01 67.975 2005-01-01 67.925 2006-01-01 68.725 2007-01-01 68.525 2008-01-01 68.950 2009-01-01 65.550 2010-01-01 63.300 2011-01-01 63.150 2012-01-01 62.325 2013-01-01 61.775 2014-01-01 62.175 2015-01-01 62.800 2016-01-01 63.875 2017-01-01 62.700