Year Percent 1999-01-01 71.000 2000-01-01 70.950 2001-01-01 71.625 2002-01-01 71.050 2003-01-01 71.050 2004-01-01 71.200 2005-01-01 71.250 2006-01-01 71.125 2007-01-01 70.650 2008-01-01 71.200 2009-01-01 71.075 2010-01-01 70.775 2011-01-01 71.075 2012-01-01 71.450 2013-01-01 71.225 2014-01-01 71.375 2015-01-01 71.050 2016-01-01 71.375 2017-01-01 71.075