Year Percent 2000-01-01 31.350 2001-01-01 30.175 2002-01-01 29.125 2003-01-01 30.150 2004-01-01 29.575 2005-01-01 30.500 2006-01-01 30.625 2007-01-01 31.800 2008-01-01 33.350 2009-01-01 34.475 2010-01-01 36.675 2011-01-01 39.625 2012-01-01 41.775 2013-01-01 43.975 2014-01-01 45.550 2015-01-01 46.875 2016-01-01 48.300 2017-01-01 50.125