Year Percent 1996-01-01 90.152000000000000 1997-01-01 81.997300000000000 1998-01-01 74.444900000000000 1999-01-01 66.440700000000000 2000-01-01 67.410900000000000 2001-01-01 69.932500000000000 2002-01-01 62.829800000000000 2003-01-01 66.379300000000000 2004-01-01 65.450000000000000 2005-01-01 65.129300000000000 2006-01-01 67.930000000000000 2007-01-01 67.903100000000000 2008-01-01 62.769900000000000 2009-01-01 59.921200000000000 2010-01-01 58.988300000000000 2011-01-01 50.965300000000000 2012-01-01 46.162900000000000 2013-01-01 42.487700000000000 2014-01-01 43.318000000000005 2015-01-01 44.802800000000000 2016-01-01 43.127400000000000