Year	Percent
1998-01-01	28.000
1999-01-01	28.050
2000-01-01	28.675
2001-01-01	29.150
2002-01-01	29.400
2003-01-01	29.800
2004-01-01	30.000
2005-01-01	29.600
2006-01-01	29.650
2007-01-01	30.175
2008-01-01	30.350
2009-01-01	29.925
2010-01-01	29.825
2011-01-01	29.475
2012-01-01	28.400
2013-01-01	27.100
2014-01-01	26.475
2015-01-01	25.950
2016-01-01	25.000
2017-01-01	24.100