Year Percent 1996-01-01 75.2254 1997-01-01 73.8539 1998-01-01 72.5623 1999-01-01 67.2921 2000-01-01 68.7221 2001-01-01 77.3729 2002-01-01 76.7120 2003-01-01 85.8863 2004-01-01 82.8763 2005-01-01 89.0526 2006-01-01 90.4519 2007-01-01 85.9515 2008-01-01 87.1968 2009-01-01 86.1002 2010-01-01 83.1055 2011-01-01 80.3455 2012-01-01 79.0029 2013-01-01 79.4062 2014-01-01 83.8886 2015-01-01 84.9931 2016-01-01 84.5182