Year	Percent
1998-01-01	61.400
1999-01-01	60.600
2000-01-01	59.925
2001-01-01	59.125
2002-01-01	58.600
2003-01-01	58.225
2004-01-01	56.200
2005-01-01	56.625
2006-01-01	56.325
2007-01-01	56.450
2008-01-01	55.500
2009-01-01	55.925
2010-01-01	55.900
2011-01-01	55.525
2012-01-01	53.925
2013-01-01	53.850
2014-01-01	53.200
2015-01-01	53.425
2016-01-01	52.500
2017-01-01	51.825