Year	Percent
1998-01-01	64.475
1999-01-01	64.550
2000-01-01	64.100
2001-01-01	63.750
2002-01-01	63.750
2003-01-01	63.425
2004-01-01	63.300
2005-01-01	63.775
2006-01-01	63.725
2007-01-01	63.400
2008-01-01	63.125
2009-01-01	63.350
2010-01-01	63.100
2011-01-01	63.075
2012-01-01	63.500
2013-01-01	64.350
2014-01-01	64.400
2015-01-01	64.625
2016-01-01	65.325
2017-01-01	65.725