Year Percent 2005-01-01 45.550 2006-01-01 46.700 2007-01-01 47.800 2008-01-01 48.500 2009-01-01 49.050 2010-01-01 49.600 2011-01-01 51.000 2012-01-01 51.225 2013-01-01 51.900 2014-01-01 52.250 2015-01-01 52.400 2016-01-01 53.550 2017-01-01 54.025