Year	Percent
1998-01-01	65.525
1999-01-01	64.125
2000-01-01	64.575
2001-01-01	63.675
2002-01-01	64.325
2003-01-01	65.250
2004-01-01	62.750
2005-01-01	62.375
2006-01-01	62.700
2007-01-01	63.175
2008-01-01	62.925
2009-01-01	62.600
2010-01-01	61.975
2011-01-01	61.600
2012-01-01	60.400
2013-01-01	62.725
2014-01-01	63.975
2015-01-01	65.025
2016-01-01	66.950
2017-01-01	69.275