Year Percent 2009-01-01 20.5042 2010-01-01 14.7932 2011-01-01 19.7152 2012-01-01 17.7232 2013-01-01 19.2345 2014-01-01 24.5653 2015-01-01 35.9901 2016-01-01 35.3264