Year	Percent
1998-01-01	75.600
1999-01-01	74.450
2000-01-01	74.600
2001-01-01	76.100
2002-01-01	74.750
2003-01-01	73.525
2004-01-01	74.700
2005-01-01	72.875
2006-01-01	71.975
2007-01-01	71.800
2008-01-01	71.325
2009-01-01	70.550
2010-01-01	68.925
2011-01-01	70.125
2012-01-01	69.925
2013-01-01	69.025
2014-01-01	70.125
2015-01-01	70.475
2016-01-01	66.400
2017-01-01	65.150