Year Percent 1996-01-01 56.1508 1997-01-01 57.5168 1998-01-01 62.5037 1999-01-01 48.5766 2000-01-01 45.3729 2001-01-01 41.5458 2002-01-01 44.2284 2003-01-01 38.5849 2004-01-01 40.3918 2005-01-01 39.3739 2006-01-01 35.6649 2007-01-01 44.5652 2008-01-01 43.7343 2009-01-01 46.4431 2010-01-01 54.0785 2011-01-01 71.1471 2012-01-01 52.7694 2013-01-01 49.3309 2014-01-01 51.0996