Year	Percent
1998-01-01	61.450
1999-01-01	61.925
2000-01-01	62.775
2001-01-01	63.425
2002-01-01	63.225
2003-01-01	62.450
2004-01-01	62.050
2005-01-01	61.750
2006-01-01	62.025
2007-01-01	62.075
2008-01-01	62.350
2009-01-01	60.575
2010-01-01	59.700
2011-01-01	58.100
2012-01-01	55.975
2013-01-01	54.975
2014-01-01	56.325
2015-01-01	57.250
2016-01-01	58.200
2017-01-01	60.250