Year Percent 2007-01-01 31.4765 2008-01-01 30.4268 2009-01-01 30.1986 2010-01-01 32.8286 2011-01-01 39.0694 2012-01-01 40.8891 2013-01-01 42.6732 2014-01-01 45.5286 2015-01-01 48.1724 2016-01-01 48.8813