Year	Percent
1998-01-01	64.750
1999-01-01	64.875
2000-01-01	65.475
2001-01-01	66.075
2002-01-01	66.625
2003-01-01	66.700
2004-01-01	66.500
2005-01-01	66.925
2006-01-01	67.275
2007-01-01	67.550
2008-01-01	67.525
2009-01-01	67.050
2010-01-01	67.050
2011-01-01	66.700
2012-01-01	66.425
2013-01-01	65.800
2014-01-01	65.575
2015-01-01	65.525
2016-01-01	65.550
2017-01-01	66.200