Year	Percent
1998-01-01	57.875
1999-01-01	57.925
2000-01-01	57.325
2001-01-01	57.650
2002-01-01	58.150
2003-01-01	60.600
2004-01-01	58.900
2005-01-01	60.825
2006-01-01	61.100
2007-01-01	60.875
2008-01-01	60.950
2009-01-01	60.175
2010-01-01	60.225
2011-01-01	57.275
2012-01-01	55.225
2013-01-01	54.975
2014-01-01	53.425
2015-01-01	54.850
2016-01-01	57.250
2017-01-01	59.850