Year Percent 2007-01-01 5.03 2008-01-01 4.48 2009-01-01 8.05 2010-01-01 9.15 2011-01-01 8.01 2012-01-01 7.93 2013-01-01 7.67 2014-01-01 7.85 2015-01-01 8.26