Year Percent 1996-01-01 96.207500000000000 1997-01-01 95.413100000000000 1998-01-01 87.935300000000000 1999-01-01 83.584500000000000 2000-01-01 80.543900000000000 2001-01-01 77.308900000000000 2002-01-01 72.930000000000000 2003-01-01 70.490000000000000 2004-01-01 67.467400000000000 2005-01-01 69.158400000000000 2006-01-01 62.845200000000000 2007-01-01 52.749100000000000 2008-01-01 47.707400000000000 2009-01-01 42.092000000000000 2010-01-01 39.053600000000000 2011-01-01 38.571700000000000 2012-01-01 35.077600000000000 2013-01-01 34.689800000000000 2014-01-01 34.001500000000000 2015-01-01 29.038800000000000 2016-01-01 27.508000000000003