Year Percent 2006-01-01 41.550 2007-01-01 41.500 2008-01-01 41.700 2009-01-01 41.150 2010-01-01 43.000 2011-01-01 44.950 2012-01-01 45.350 2013-01-01 45.900 2014-01-01 45.500 2015-01-01 45.975 2016-01-01 46.325 2017-01-01 47.075