Year Percent 1998-01-01 12.5000 1999-01-01 13.5000 2000-01-01 13.3000 2001-01-01 12.7000 2002-01-01 14.0000 2003-01-01 14.1000 2004-01-01 13.6000 2005-01-01 13.0000 2006-01-01 12.5000 2007-01-01 12.2000 2008-01-01 12.5000 2009-01-01 14.3000 2010-01-01 14.1384 2011-01-01 13.9346 2012-01-01 13.3121 2013-01-01 13.3244 2014-01-01 13.3851 2015-01-01 12.6204 2016-01-01 13.7798