Year Percent 2005-01-01 6.400 2006-01-01 6.175 2007-01-01 5.475 2008-01-01 5.025 2009-01-01 6.200 2010-01-01 6.775 2011-01-01 6.750 2012-01-01 7.275 2013-01-01 7.700 2014-01-01 7.400 2015-01-01 6.975 2016-01-01 6.475 2017-01-01 5.850