Year Percent 1999-01-01 7.700 2000-01-01 8.275 2001-01-01 8.675 2002-01-01 8.100 2003-01-01 8.250 2004-01-01 8.450 2005-01-01 8.300 2006-01-01 7.700 2007-01-01 7.650 2008-01-01 6.725 2009-01-01 7.850 2010-01-01 7.975 2011-01-01 8.450 2012-01-01 9.350 2013-01-01 9.850 2014-01-01 9.700 2015-01-01 9.200 2016-01-01 9.200 2017-01-01 10.400