Year	Percent
1998-01-01	76.050
1999-01-01	75.575
2000-01-01	76.350
2001-01-01	75.425
2002-01-01	72.800
2003-01-01	70.050
2004-01-01	68.675
2005-01-01	67.025
2006-01-01	66.000
2007-01-01	64.800
2008-01-01	63.900
2009-01-01	62.825
2010-01-01	62.050
2011-01-01	60.600
2012-01-01	58.450
2013-01-01	55.775
2014-01-01	53.650
2015-01-01	51.750
2016-01-01	48.775
2017-01-01	45.450