Year	Percent
1998-01-01	39.200
1999-01-01	39.250
2000-01-01	39.850
2001-01-01	40.250
2002-01-01	40.425
2003-01-01	40.750
2004-01-01	40.900
2005-01-01	40.625
2006-01-01	40.750
2007-01-01	41.250
2008-01-01	41.500
2009-01-01	41.325
2010-01-01	41.550
2011-01-01	41.750
2012-01-01	41.350
2013-01-01	40.725
2014-01-01	40.700
2015-01-01	40.600
2016-01-01	40.075
2017-01-01	39.775