Year Percent 2009-01-01 14 2010-01-01 14.0 2011-01-01 14.0 2012-01-01 14.0 2013-01-01 14.0 2014-01-01 14.0 2015-01-01 14.0 2016-01-01 14.0 2017-01-01 18.9