Year	Percent
1998-01-01	60.475
1999-01-01	60.550
2000-01-01	60.575
2001-01-01	60.900
2002-01-01	60.025
2003-01-01	59.650
2004-01-01	59.425
2005-01-01	59.675
2006-01-01	60.475
2007-01-01	61.125
2008-01-01	61.850
2009-01-01	58.525
2010-01-01	58.325
2011-01-01	58.875
2012-01-01	58.425
2013-01-01	57.425
2014-01-01	56.775
2015-01-01	56.275
2016-01-01	56.775
2017-01-01	57.200