Year	Percent
1998-01-01	53.525
1999-01-01	51.400
2000-01-01	48.350
2001-01-01	45.150
2002-01-01	42.225
2003-01-01	39.600
2004-01-01	38.750
2005-01-01	38.850
2006-01-01	37.725
2007-01-01	36.725
2008-01-01	35.900
2009-01-01	37.250
2010-01-01	36.200
2011-01-01	35.475
2012-01-01	36.450
2013-01-01	36.775
2014-01-01	38.075
2015-01-01	37.375
2016-01-01	37.450
2017-01-01	36.450