Year Percent 2003-01-01 3.000 2004-01-01 3.700 2005-01-01 3.500 2006-01-01 3.600 2007-01-01 3.550 2008-01-01 4.300 2009-01-01 4.400 2010-01-01 3.825 2011-01-01 3.900 2012-01-01 4.575 2013-01-01 5.525 2014-01-01 5.975 2015-01-01 6.150 2016-01-01 6.025 2017-01-01 5.550