Year Percent 1999-01-01 12.750 2000-01-01 15.150 2001-01-01 15.975 2002-01-01 14.950 2003-01-01 14.525 2004-01-01 14.725 2005-01-01 13.275 2006-01-01 10.475 2007-01-01 8.650 2008-01-01 7.400 2009-01-01 10.000 2010-01-01 12.400 2011-01-01 11.750 2012-01-01 11.500 2013-01-01 12.200 2014-01-01 11.525 2015-01-01 9.050 2016-01-01 7.675 2017-01-01 7.300