Year Percent 1999-01-01 6.350 2000-01-01 5.050 2001-01-01 4.300 2002-01-01 4.750 2003-01-01 5.350 2004-01-01 5.625 2005-01-01 5.825 2006-01-01 4.300 2007-01-01 3.950 2008-01-01 2.825 2009-01-01 3.350 2010-01-01 3.950 2011-01-01 4.725 2012-01-01 5.275 2013-01-01 5.050 2014-01-01 4.525 2015-01-01 4.800 2016-01-01 4.100 2017-01-01 3.600