Year	Percent
1998-01-01	6.40
1999-01-01	6.00
2000-01-01	6.00
2001-01-01	10.60
2002-01-01	8.80
2003-01-01	12.50
2004-01-01	11.00
2005-01-01	7.00
2006-01-01	4.60
2007-01-01	3.20
2008-01-01	2.00
2009-01-01	2.70
2010-01-01	2.70
2011-01-01	2.20
2012-01-01	2.10
2013-01-01	2.00
2014-01-01	1.94
2015-01-01	1.80