Year	Percent
1998-01-01	29.375
1999-01-01	29.100
2000-01-01	28.550
2001-01-01	27.950
2002-01-01	27.350
2003-01-01	27.175
2004-01-01	27.275
2005-01-01	26.800
2006-01-01	26.400
2007-01-01	26.125
2008-01-01	26.025
2009-01-01	26.600
2010-01-01	26.325
2011-01-01	26.375
2012-01-01	26.575
2013-01-01	26.950
2014-01-01	26.750
2015-01-01	26.600
2016-01-01	26.300
2017-01-01	25.325