Year Percent 1996-01-01 95.1600 1997-01-01 95.9636 1998-01-01 97.4773 1999-01-01 98.0124 2000-01-01 95.0814 2001-01-01 81.3406 2002-01-01 68.3423 2003-01-01 64.3654 2004-01-01 57.5953 2005-01-01 59.3151 2006-01-01 55.3162 2007-01-01 54.6188 2008-01-01 54.4626 2009-01-01 52.8016 2010-01-01 49.4349 2011-01-01 53.2550 2012-01-01 54.8828 2013-01-01 58.2318 2014-01-01 60.8400 2015-01-01 71.1855 2016-01-01 66.6989