Year Percent 1989-01-01 90.97700000000000 1990-01-01 86.58190000000000 1991-01-01 83.88790000000000 1992-01-01 86.09420000000000 1993-01-01 86.19010000000000 1994-01-01 88.59700000000001 1995-01-01 92.94010000000000 1996-01-01 95.26260000000000 1997-01-01 95.57590000000000 1998-01-01 95.95690000000000 1999-01-01 96.10960000000000 2000-01-01 96.01820000000000 2001-01-01 95.45190000000000 2002-01-01 94.51810000000000 2003-01-01 93.25800000000000 2004-01-01 93.94030000000000 2005-01-01 95.07920000000000 2006-01-01 94.61890000000000 2007-01-01 95.06980000000000 2008-01-01 97.72420000000000 2009-01-01 97.72420000000000 2010-01-01 97.72420000000000 2011-01-01 97.72420000000000 2012-01-01 99.95340000000000 2013-01-01 99.92380000000000 2014-01-01 99.81290000000000 2015-01-01 99.62370000000000 2016-01-01 99.57330000000000