Year	Percent
1998-01-01	72.000
1999-01-01	71.950
2000-01-01	71.325
2001-01-01	70.850
2002-01-01	70.600
2003-01-01	70.200
2004-01-01	70.000
2005-01-01	70.400
2006-01-01	70.350
2007-01-01	69.825
2008-01-01	69.650
2009-01-01	70.075
2010-01-01	70.175
2011-01-01	70.525
2012-01-01	71.600
2013-01-01	72.900
2014-01-01	73.525
2015-01-01	74.050
2016-01-01	75.000
2017-01-01	75.900