Year	Percent
1998-01-01	4.700
1999-01-01	4.600
2000-01-01	4.375
2001-01-01	4.475
2002-01-01	3.950
2003-01-01	3.600
2004-01-01	4.225
2005-01-01	3.625
2006-01-01	2.875
2007-01-01	2.575
2008-01-01	3.225
2009-01-01	3.750
2010-01-01	3.900
2011-01-01	4.550
2012-01-01	5.950
2013-01-01	6.700
2014-01-01	6.200
2015-01-01	6.400
2016-01-01	6.425
2017-01-01	6.300