Year Percent 2003-01-01 41.600 2004-01-01 42.200 2005-01-01 43.700 2006-01-01 46.300 2007-01-01 48.000 2008-01-01 45.125 2009-01-01 46.850 2010-01-01 47.225 2011-01-01 47.100 2012-01-01 48.800 2013-01-01 49.125 2014-01-01 50.375 2015-01-01 50.575 2016-01-01 49.975 2017-01-01 51.950