Year	Percent
1998-01-01	69.725
1999-01-01	69.300
2000-01-01	69.025
2001-01-01	68.450
2002-01-01	68.675
2003-01-01	69.125
2004-01-01	69.425
2005-01-01	69.625
2006-01-01	69.925
2007-01-01	69.950
2008-01-01	70.200
2009-01-01	70.300
2010-01-01	70.025
2011-01-01	68.800
2012-01-01	68.175
2013-01-01	68.000
2014-01-01	67.275
2015-01-01	67.025
2016-01-01	67.225
2017-01-01	67.425