Year Percent 1993-01-01 98.6868 1994-01-01 99.0855 1995-01-01 99.3334 1996-01-01 99.3914 1997-01-01 99.7818 1998-01-01 99.9785 1999-01-01 99.7956 2000-01-01 99.6105 2001-01-01 99.7886 2002-01-01 99.9499 2003-01-01 99.9752 2004-01-01 99.9768 2005-01-01 99.9785 2006-01-01 99.9811 2007-01-01 99.9847 2008-01-01 99.9877 2009-01-01 99.9887 2010-01-01 99.9896 2011-01-01 99.9509 2012-01-01 99.9527 2013-01-01 99.9931 2014-01-01 99.9939 2015-01-01 99.9935 2016-01-01 99.9931