Year	Percent
1998-01-01	67.875
1999-01-01	67.125
2000-01-01	66.600
2001-01-01	66.650
2002-01-01	66.075
2003-01-01	65.675
2004-01-01	65.100
2005-01-01	64.975
2006-01-01	65.250
2007-01-01	65.350
2008-01-01	65.850
2009-01-01	64.275
2010-01-01	64.150
2011-01-01	64.275
2012-01-01	63.775
2013-01-01	62.975
2014-01-01	62.600
2015-01-01	62.475
2016-01-01	62.425
2017-01-01	62.725