Year Percent 1996-01-01 73.7026 1997-01-01 70.7177 1998-01-01 70.0444 1999-01-01 76.1344 2000-01-01 75.6090 2001-01-01 83.4488 2002-01-01 82.6732 2003-01-01 88.3289 2004-01-01 87.6133 2005-01-01 88.6682 2006-01-01 90.4104 2007-01-01 91.8493 2008-01-01 90.8806 2009-01-01 90.0946 2010-01-01 88.2903 2011-01-01 87.6378 2012-01-01 88.2404 2013-01-01 88.0488 2014-01-01 88.5543 2015-01-01 86.3101 2016-01-01 87.4624