Year Percent 2005-01-01 11.550 2006-01-01 10.475 2007-01-01 8.650 2008-01-01 7.575 2009-01-01 8.250 2010-01-01 7.500 2011-01-01 6.125 2012-01-01 5.700 2013-01-01 5.625 2014-01-01 5.400 2015-01-01 5.125 2016-01-01 4.575 2017-01-01 4.250