Year	Percent
1998-01-01	68.700
1999-01-01	69.725
2000-01-01	70.225
2001-01-01	70.450
2002-01-01	69.925
2003-01-01	69.675
2004-01-01	69.250
2005-01-01	69.325
2006-01-01	69.800
2007-01-01	70.000
2008-01-01	70.650
2009-01-01	69.050
2010-01-01	69.075
2011-01-01	69.325
2012-01-01	68.925
2013-01-01	68.200
2014-01-01	68.025
2015-01-01	68.025
2016-01-01	68.125
2017-01-01	68.650