Year Percent 2002-01-01 5.60 2003-01-01 6.10 2004-01-01 6.07 2005-01-01 6.16 2006-01-01 6.57 2007-01-01 6.45 2008-01-01 5.98 2009-01-01 6.45 2010-01-01 6.50 2011-01-01 6.63 2012-01-01 7.11 2013-01-01 7.70 2014-01-01 7.95 2015-01-01 8.34 2016-01-01 8.46