Year Percent 2000-01-01 53.475 2001-01-01 51.950 2002-01-01 50.725 2003-01-01 49.775 2004-01-01 49.200 2005-01-01 46.925 2006-01-01 45.575 2007-01-01 44.750 2008-01-01 44.275 2009-01-01 45.175 2010-01-01 44.900 2011-01-01 44.525 2012-01-01 44.850 2013-01-01 42.450 2014-01-01 41.450 2015-01-01 39.725 2016-01-01 38.900 2017-01-01 37.800