Year	Percent
1998-01-01	45.1
1999-01-01	42.5
2000-01-01	47.2
2001-01-01	49.3
2002-01-01	56.9
2003-01-01	63.6
2004-01-01	63.1
2005-01-01	61.2
2006-01-01	60
2007-01-01	35.8
2008-01-01	35.8
2009-01-01	35.8
2010-01-01	35.8