Year Percent 1995-01-01 0.29301300000000000 1996-01-01 0.35559000000000000 1997-01-01 0.32268300000000000 1998-01-01 0.35855100000000000 1999-01-01 0.29089699999999996 2000-01-01 0.33991400000000000 2001-01-01 0.38522000000000000 2002-01-01 0.48137500000000000 2003-01-01 0.53718500000000000 2004-01-01 0.56954100000000000 2005-01-01 0.50859500000000000 2006-01-01 0.50859100000000000 2007-01-01 0.57402700000000010 2008-01-01 0.57482900000000000 2009-01-01 0.64580700000000000 2010-01-01 0.67429300000000000 2011-01-01 0.62597300000000000 2012-01-01 0.58020200000000000 2013-01-01 0.53997700000000000 2014-01-01 0.54416999999999990 2015-01-01 0.57929200000000000