Year Percent 1996-01-01 97.16330000000000 1997-01-01 96.89360000000000 1998-01-01 96.46590000000000 1999-01-01 96.14670000000000 2000-01-01 95.79260000000000 2001-01-01 95.12040000000000 2002-01-01 95.61840000000000 2003-01-01 96.13820000000000 2004-01-01 95.32680000000000 2005-01-01 93.62860000000000 2006-01-01 92.90220000000000 2007-01-01 93.05770000000000 2008-01-01 93.10799999999999 2009-01-01 89.05090000000000 2010-01-01 88.28910000000000 2011-01-01 87.79410000000000 2012-01-01 88.88560000000000 2013-01-01 87.31650000000000 2014-01-01 86.31020000000000 2015-01-01 76.22500000000000 2016-01-01 75.08900000000000