Year	Percent
1998-01-01	41.975
1999-01-01	42.050
2000-01-01	40.575
2001-01-01	37.925
2002-01-01	35.250
2003-01-01	33.975
2004-01-01	31.525
2005-01-01	28.900
2006-01-01	29.150
2007-01-01	26.875
2008-01-01	26.100
2009-01-01	26.100
2010-01-01	25.275
2011-01-01	24.100
2012-01-01	25.950
2013-01-01	26.075
2014-01-01	26.075
2015-01-01	27.350
2016-01-01	26.225
2017-01-01	26.575