Year Percent 1998-01-01 0.44017600000000000 1999-01-01 0.42265600000000003 2000-01-01 0.46860600000000000 2001-01-01 0.42008599999999996 2002-01-01 0.41397100000000000 2003-01-01 0.43031899999999995 2004-01-01 0.43355200000000005 2005-01-01 0.44998500000000000 2006-01-01 0.44533100000000003 2007-01-01 0.47740900000000003 2008-01-01 0.42954799999999993 2009-01-01 0.47673500000000000 2010-01-01 0.46882100000000000 2011-01-01 0.48180400000000000 2012-01-01 0.42984500000000000 2013-01-01 0.47222500000000000 2014-01-01 0.40883800000000003 2015-01-01 0.44911400000000000