Year	Percent
1999-01-01	40.275
2000-01-01	39.950
2001-01-01	39.475
2002-01-01	39.950
2003-01-01	39.750
2004-01-01	39.875
2005-01-01	40.525
2006-01-01	40.850
2007-01-01	41.150
2008-01-01	40.675
2009-01-01	41.150
2010-01-01	41.000
2011-01-01	41.225
2012-01-01	40.800
2013-01-01	40.725
2014-01-01	40.625
2015-01-01	40.350
2016-01-01	39.950
2017-01-01	40.075