Year	Percent
1998-01-01	60.800
1999-01-01	60.750
2000-01-01	60.150
2001-01-01	59.750
2002-01-01	59.575
2003-01-01	59.250
2004-01-01	59.100
2005-01-01	59.375
2006-01-01	59.250
2007-01-01	58.750
2008-01-01	58.500
2009-01-01	58.675
2010-01-01	58.450
2011-01-01	58.250
2012-01-01	58.650
2013-01-01	59.275
2014-01-01	59.300
2015-01-01	59.400
2016-01-01	59.925
2017-01-01	60.225