Year Percent 1991-01-01 0.26763700000000000 1992-01-01 0.21971800000000000 1993-01-01 0.22077399999999997 1994-01-01 0.21565600000000000 1995-01-01 0.25168000000000000 1996-01-01 0.41101499999999996 1997-01-01 0.40328000000000000 1998-01-01 0.37729400000000000 1999-01-01 0.36051700000000003 2000-01-01 0.37194400000000000 2001-01-01 0.41809700000000005 2002-01-01 0.45767800000000000 2003-01-01 0.48121300000000000 2004-01-01 0.54235200000000010 2005-01-01 0.53046000000000000 2006-01-01 0.44697000000000000 2007-01-01 0.50457000000000000 2008-01-01 0.56485600000000000 2009-01-01 0.54666300000000000 2010-01-01 0.55991499999999990 2011-01-01 0.60651499999999990 2012-01-01 0.56468999999999990 2013-01-01 0.50812400000000000 2014-01-01 0.42178000000000004 2015-01-01 0.53754099999999990 2016-01-01 0.49786600000000000