Year Percent 2006-01-01 5.9 2007-01-01 5.5 2008-01-01 6.0 2009-01-01 8.6 2010-01-01 8.7 2011-01-01 8.1 2012-01-01 8.1 2013-01-01 8.1 2014-01-01 7.5 2015-01-01 6.9 2016-01-01 6.4