Year Percent 1996-01-01 23.0000 1997-01-01 30.0613 1998-01-01 26.1146 1999-01-01 23.8095 2000-01-01 21.6374 2001-01-01 21.3115 2002-01-01 22.7488 2003-01-01 23.6967 2004-01-01 23.3184 2005-01-01 23.2365 2006-01-01 25.5892 2007-01-01 31.7585 2008-01-01 32.9918 2009-01-01 32.6642 2010-01-01 25.0943 2011-01-01 27.5168 2012-01-01 27.3669 2013-01-01 28.6501 2014-01-01 31.1111