Year Percent 1999-01-01 43.750 2000-01-01 45.600 2001-01-01 46.800 2002-01-01 47.750 2003-01-01 48.775 2004-01-01 49.900 2005-01-01 51.875 2006-01-01 53.050 2007-01-01 53.750 2008-01-01 52.675 2009-01-01 48.850 2010-01-01 47.775 2011-01-01 46.925 2012-01-01 44.925 2013-01-01 43.875 2014-01-01 44.525 2015-01-01 45.875 2016-01-01 47.050 2017-01-01 48.125