Year Percent 2000-01-01 40.400 2001-01-01 39.550 2002-01-01 38.750 2003-01-01 39.675 2004-01-01 39.050 2005-01-01 40.850 2006-01-01 42.500 2007-01-01 44.750 2008-01-01 46.750 2009-01-01 47.475 2010-01-01 48.900 2011-01-01 51.600 2012-01-01 53.525 2013-01-01 55.925 2014-01-01 57.200 2015-01-01 57.550 2016-01-01 58.650 2017-01-01 60.800