Year	Percent
1998-01-01	9.400
1999-01-01	9.200
2000-01-01	8.550
2001-01-01	7.900
2002-01-01	7.525
2003-01-01	7.250
2004-01-01	6.825
2005-01-01	6.650
2006-01-01	5.875
2007-01-01	5.300
2008-01-01	5.950
2009-01-01	6.925
2010-01-01	7.500
2011-01-01	7.475
2012-01-01	9.575
2013-01-01	11.200
2014-01-01	11.850
2015-01-01	11.150
2016-01-01	11.100
2017-01-01	10.850