Year Percent 1991-01-01 96.41890000000000 1992-01-01 96.27190000000000 1993-01-01 90.26880000000000 1994-01-01 80.41100000000000 1995-01-01 86.63799999999999 1996-01-01 78.94170000000000 1997-01-01 72.03760000000000 1998-01-01 80.93220000000000 1999-01-01 83.00170000000000 2000-01-01 84.67850000000000 2001-01-01 89.88120000000000 2002-01-01 97.08840000000000 2003-01-01 99.46440000000000 2004-01-01 91.69890000000000 2005-01-01 88.20500000000000 2006-01-01 94.03040000000000 2007-01-01 98.89190000000000 2008-01-01 98.89190000000000 2009-01-01 92.72100000000000 2010-01-01 88.98670000000000 2011-01-01 92.75830000000000 2012-01-01 95.80600000000000 2013-01-01 99.17480000000000 2014-01-01 98.14130000000000 2015-01-01 96.39010000000000 2016-01-01 94.32420000000000