Year	Percent
1998-01-01	63.325
1999-01-01	62.200
2000-01-01	61.425
2001-01-01	61.550
2002-01-01	61.375
2003-01-01	60.875
2004-01-01	60.475
2005-01-01	60.750
2006-01-01	61.025
2007-01-01	61.225
2008-01-01	61.475
2009-01-01	60.500
2010-01-01	59.950
2011-01-01	59.925
2012-01-01	59.750
2013-01-01	59.150
2014-01-01	58.950
2015-01-01	58.950
2016-01-01	58.625
2017-01-01	58.875