Year Percent 1996-01-01 0.4548010000000000 1997-01-01 0.4223490000000000 1998-01-01 0.4223490000000000 1999-01-01 0.5128880000000000 2000-01-01 0.5040450000000000 2001-01-01 0.5512830000000000 2002-01-01 0.6414910000000000 2003-01-01 0.6766220000000001 2004-01-01 0.7981800000000000 2005-01-01 0.8483060000000000 2006-01-01 0.7951590000000001 2007-01-01 1.0764799999999999 2008-01-01 1.0830100000000000 2009-01-01 0.8219350000000001 2010-01-01 0.8512520000000000 2011-01-01 0.8848770000000000 2012-01-01 0.8256879999999999 2013-01-01 0.8278810000000000 2014-01-01 0.8140100000000000 2015-01-01 0.8549110000000001