Year	Percent
1998-01-01	13.425
1999-01-01	13.050
2000-01-01	12.075
2001-01-01	11.100
2002-01-01	10.500
2003-01-01	9.975
2004-01-01	9.175
2005-01-01	8.925
2006-01-01	7.800
2007-01-01	7.100
2008-01-01	7.725
2009-01-01	8.450
2010-01-01	8.900
2011-01-01	8.775
2012-01-01	10.925
2013-01-01	12.325
2014-01-01	13.150
2015-01-01	12.200
2016-01-01	12.475
2017-01-01	12.300