Year Percent 1992-01-01 87.4907 1993-01-01 83.8498 1994-01-01 68.9265 1995-01-01 71.8903 1996-01-01 81.8175 1997-01-01 83.3748 1998-01-01 64.7848 1999-01-01 50.5242 2000-01-01 48.7373 2001-01-01 51.5896 2002-01-01 64.4183 2003-01-01 81.1667 2004-01-01 85.8968 2005-01-01 89.6876 2006-01-01 93.0112 2007-01-01 95.5856 2008-01-01 97.2550 2009-01-01 96.4723 2010-01-01 90.4437 2011-01-01 84.4062 2012-01-01 83.3478 2013-01-01 84.8836 2014-01-01 87.0880 2015-01-01 86.0801 2016-01-01 85.2577