Year	Percent
1998-01-01	11.850
1999-01-01	11.450
2000-01-01	10.600
2001-01-01	9.550
2002-01-01	9.025
2003-01-01	8.700
2004-01-01	8.025
2005-01-01	7.750
2006-01-01	6.775
2007-01-01	6.075
2008-01-01	6.725
2009-01-01	7.750
2010-01-01	8.350
2011-01-01	8.375
2012-01-01	10.700
2013-01-01	12.175
2014-01-01	12.725
2015-01-01	11.925
2016-01-01	11.725
2017-01-01	11.250