Year	Percent
1998-01-01	24.925
1999-01-01	24.275
2000-01-01	22.600
2001-01-01	21.850
2002-01-01	21.675
2003-01-01	20.375
2004-01-01	19.450
2005-01-01	18.325
2006-01-01	17.375
2007-01-01	17.250
2008-01-01	17.125
2009-01-01	16.725
2010-01-01	15.150
2011-01-01	15.500
2012-01-01	14.950
2013-01-01	14.475
2014-01-01	14.150
2015-01-01	13.950
2016-01-01	13.425
2017-01-01	12.975