Year Percent 2006-01-01 64.400 2007-01-01 64.300 2008-01-01 64.200 2009-01-01 62.450 2010-01-01 64.450 2011-01-01 66.900 2012-01-01 66.775 2013-01-01 67.125 2014-01-01 66.950 2015-01-01 67.125 2016-01-01 67.275 2017-01-01 67.750