Year Percent 1991-01-01 93.91530000000000 1992-01-01 95.31140000000000 1993-01-01 96.60330000000000 1994-01-01 97.18040000000000 1995-01-01 98.11070000000000 1996-01-01 98.46970000000000 1997-01-01 98.63270000000000 1998-01-01 98.82640000000000 1999-01-01 98.99799999999999 2000-01-01 99.10160000000000 2001-01-01 99.37330000000000 2002-01-01 99.62330000000000 2003-01-01 99.38530000000000 2004-01-01 99.24250000000000 2005-01-01 99.46440000000000 2006-01-01 99.64770000000000 2007-01-01 99.72220000000000 2008-01-01 99.76860000000000 2009-01-01 99.65030000000000 2010-01-01 99.56470000000000 2011-01-01 99.65460000000000 2012-01-01 99.53630000000000 2013-01-01 99.30520000000000 2014-01-01 99.17120000000000 2015-01-01 95.61450000000000 2016-01-01 88.58740000000000