Year Percent 2005-01-01 53.550 2006-01-01 56.100 2007-01-01 59.425 2008-01-01 61.700 2009-01-01 63.750 2010-01-01 65.200 2011-01-01 67.100 2012-01-01 68.600 2013-01-01 69.900 2014-01-01 71.375 2015-01-01 71.325 2016-01-01 73.700 2017-01-01 75.000