Year Percent 1993-01-01 99.9051 1994-01-01 99.3311 1995-01-01 99.8999 1996-01-01 99.8575 1997-01-01 99.3546 1998-01-01 98.7021 1999-01-01 98.7021 2000-01-01 98.7021 2001-01-01 97.8562 2002-01-01 97.9225 2003-01-01 98.0297 2004-01-01 98.4032 2005-01-01 98.7065 2006-01-01 99.1296 2007-01-01 99.1560 2008-01-01 99.0978 2009-01-01 99.2110 2010-01-01 99.2274 2011-01-01 99.2770 2012-01-01 98.5632 2013-01-01 97.1019 2014-01-01 96.6235 2015-01-01 96.7853 2016-01-01 96.8478