Year Percent 1996-01-01 79.09520000000000 1997-01-01 94.68740000000000 1998-01-01 81.55470000000000 1999-01-01 78.56450000000000 2000-01-01 57.94910000000000 2001-01-01 60.75210000000000 2002-01-01 63.16940000000000 2003-01-01 68.49270000000000 2004-01-01 67.72150000000000 2005-01-01 67.80199999999999 2006-01-01 66.92810000000000 2007-01-01 67.51190000000000 2008-01-01 74.22050000000000 2009-01-01 71.97800000000001 2010-01-01 74.33670000000000 2011-01-01 64.96290000000000 2012-01-01 65.13200000000000 2013-01-01 65.60170000000000 2014-01-01 72.03790000000000 2015-01-01 76.21920000000000 2016-01-01 75.60130000000000