Year	Percent
1999-01-01	69.500
2000-01-01	68.850
2001-01-01	68.350
2002-01-01	68.225
2003-01-01	68.525
2004-01-01	66.125
2005-01-01	66.375
2006-01-01	66.725
2007-01-01	67.600
2008-01-01	67.475
2009-01-01	67.325
2010-01-01	67.100
2011-01-01	66.875
2012-01-01	66.925
2013-01-01	66.950
2014-01-01	66.425
2015-01-01	66.400
2016-01-01	66.800
2017-01-01	66.825