Year Percent 2008-01-01 30.7501 2009-01-01 32.4160 2010-01-01 39.6177 2011-01-01 37.9207 2012-01-01 38.3845 2013-01-01 37.6812 2014-01-01 38.8664 2015-01-01 39.4775 2016-01-01 40.2739