Year Percent 1999-01-01 0.74202900000000000 2000-01-01 0.73343600000000000 2001-01-01 0.65534300000000000 2002-01-01 0.54494500000000000 2003-01-01 0.38898699999999997 2004-01-01 0.48608900000000005 2005-01-01 0.47965699999999994 2006-01-01 0.43982600000000000 2007-01-01 0.35320999999999997 2008-01-01 0.31193200000000004 2009-01-01 0.20441199999999998 2010-01-01 0.19553800000000002 2011-01-01 0.15264700000000000 2012-01-01 0.14985900000000000 2013-01-01 0.19687600000000000 2014-01-01 0.27871399999999996 2015-01-01 0.31359100000000000 2016-01-01 0.54493400000000000 2017-01-01 0.53778700000000000