Year Percent 1996-01-01 80.5706 1997-01-01 80.4110 1998-01-01 79.5336 1999-01-01 78.3189 2000-01-01 78.2834 2001-01-01 85.0712 2002-01-01 86.1833 2003-01-01 85.6668 2004-01-01 84.8107 2005-01-01 81.9079 2006-01-01 80.5764 2007-01-01 80.7454 2008-01-01 81.1202 2009-01-01 80.2715 2010-01-01 81.6791 2011-01-01 81.9322 2012-01-01 81.5586 2013-01-01 81.2826 2014-01-01 81.0070 2015-01-01 81.4551 2016-01-01 86.6028