Year Percent 2011-01-01 7.8514600000000000 2012-01-01 7.8514600000000000 2013-01-01 7.8514600000000000 2014-01-01 7.6845800000000000 2015-01-01 7.6845800000000000 2016-01-01 7.6845800000000000 2017-01-01 7.4722100000000005