Year	Percent
1998-01-01	66.800
1999-01-01	67.275
2000-01-01	68.000
2001-01-01	68.550
2002-01-01	69.075
2003-01-01	69.600
2004-01-01	70.150
2005-01-01	69.900
2006-01-01	70.425
2007-01-01	70.575
2008-01-01	70.150
2009-01-01	68.500
2010-01-01	67.525
2011-01-01	67.250
2012-01-01	66.375
2013-01-01	64.650
2014-01-01	64.675
2015-01-01	65.500
2016-01-01	66.425
2017-01-01	67.025