Year	Percent
1998-01-01	2.4
1999-01-01	2.5
2000-01-01	1.5
2001-01-01	1.2
2002-01-01	2.6
2003-01-01	2.1
2004-01-01	0.9
2005-01-01	1.1
2006-01-01	0.8
2007-01-01	0.8
2008-01-01	0.8
2009-01-01	14.1
2010-01-01	18.3
2011-01-01	11.6
2012-01-01	6.8
2013-01-01	4.5
2014-01-01	2.5
2015-01-01	1.7