Year Percent 2011-01-01 7.2563699999999995 2012-01-01 7.2563699999999995 2013-01-01 7.2563699999999995 2014-01-01 9.4713900000000000 2015-01-01 9.4713900000000000 2016-01-01 9.4713900000000000 2017-01-01 8.6094900000000000