Year	Percent
1998-01-01	70.025
1999-01-01	69.950
2000-01-01	70.500
2001-01-01	70.625
2002-01-01	71.600
2003-01-01	72.825
2004-01-01	73.425
2005-01-01	74.000
2006-01-01	75.250
2007-01-01	75.425
2008-01-01	76.000
2009-01-01	75.275
2010-01-01	73.150
2011-01-01	68.825
2012-01-01	63.875
2013-01-01	61.325
2014-01-01	62.400
2015-01-01	64.500
2016-01-01	65.975
2017-01-01	67.375