Year Percent 2000-01-01 41.675 2001-01-01 43.025 2002-01-01 44.525 2003-01-01 46.275 2004-01-01 46.925 2005-01-01 48.000 2006-01-01 48.975 2007-01-01 48.850 2008-01-01 49.000 2009-01-01 49.175 2010-01-01 49.475 2011-01-01 49.500 2012-01-01 51.025 2013-01-01 53.025 2014-01-01 54.425 2015-01-01 55.950 2016-01-01 57.400 2017-01-01 59.075