Year	Percent
1998-01-01	61.125
1999-01-01	58.175
2000-01-01	55.500
2001-01-01	50.675
2002-01-01	48.775
2003-01-01	47.775
2004-01-01	45.725
2005-01-01	43.625
2006-01-01	41.825
2007-01-01	41.575
2008-01-01	41.200
2009-01-01	40.425
2010-01-01	39.700
2011-01-01	39.600
2012-01-01	37.075
2013-01-01	35.725
2014-01-01	34.450
2015-01-01	32.825
2016-01-01	32.350
2017-01-01	31.850