Year Percent 1993-01-01 88.6762 1994-01-01 86.9540 1995-01-01 77.7661 1996-01-01 62.6784 1997-01-01 58.9641 1998-01-01 57.6469 1999-01-01 58.8232 2000-01-01 75.7593 2001-01-01 93.4140 2002-01-01 96.8749 2003-01-01 98.4836 2004-01-01 99.3333 2005-01-01 99.2208 2006-01-01 99.4208 2007-01-01 99.6350 2008-01-01 99.3603 2009-01-01 98.4327 2010-01-01 98.8591 2011-01-01 99.8536 2012-01-01 99.5005 2013-01-01 98.6058 2014-01-01 97.3824 2015-01-01 94.8089 2016-01-01 92.9545