Year Percent 1996-01-01 79.7058 1997-01-01 70.9579 1998-01-01 66.8117 1999-01-01 65.1073 2000-01-01 73.8498 2001-01-01 67.6220 2002-01-01 60.2357 2003-01-01 62.2443 2004-01-01 65.4122 2005-01-01 58.0448 2006-01-01 57.6342 2007-01-01 56.4100 2008-01-01 65.7603 2009-01-01 52.8946 2010-01-01 54.5676 2011-01-01 56.6625 2012-01-01 56.1919 2013-01-01 60.4029 2014-01-01 59.9345