Year Percent 1996-01-01 3.9583600000000000 1997-01-01 4.4440300000000010 1998-01-01 4.1200500000000000 1999-01-01 3.9094700000000000 2000-01-01 4.3009300000000000 2001-01-01 4.0548100000000000 2002-01-01 3.9604600000000000 2003-01-01 4.0775500000000000 2004-01-01 3.6810900000000000 2005-01-01 3.3796100000000000 2006-01-01 3.6170199999999997 2007-01-01 3.4483500000000000 2008-01-01 3.4928400000000000 2009-01-01 3.3961200000000000 2010-01-01 3.4474400000000003 2011-01-01 3.6890800000000000 2012-01-01 3.3832400000000002 2013-01-01 3.2364400000000000 2014-01-01 2.9873000000000000 2015-01-01 2.8924900000000000 2016-01-01 3.4304300000000003