Year	Percent
1998-01-01	13.100
1999-01-01	11.075
2000-01-01	9.225
2001-01-01	9.250
2002-01-01	8.525
2003-01-01	7.725
2004-01-01	7.400
2005-01-01	7.200
2006-01-01	6.875
2007-01-01	6.825
2008-01-01	5.775
2009-01-01	7.025
2010-01-01	7.400
2011-01-01	7.525
2012-01-01	8.125
2013-01-01	8.100
2014-01-01	8.275
2015-01-01	9.150
2016-01-01	8.200
2017-01-01	8.675