Year	Percent
1998-01-01	3.30
1999-01-01	3.65
2000-01-01	2.80
2001-01-01	2.80
2002-01-01	3.00
2003-01-01	2.40
2004-01-01	2.25
2005-01-01	2.00
2006-01-01	1.70
2007-01-01	1.80
2008-01-01	2.80
2009-01-01	4.80
2010-01-01	5.38
2011-01-01	6.01
2012-01-01	7.48
2013-01-01	7.68
2014-01-01	8.19
2015-01-01	5.98