Year	Percent
1998-01-01	56.125
1999-01-01	55.800
2000-01-01	55.400
2001-01-01	55.925
2002-01-01	55.800
2003-01-01	55.425
2004-01-01	55.175
2005-01-01	55.650
2006-01-01	56.325
2007-01-01	57.050
2008-01-01	57.550
2009-01-01	55.500
2010-01-01	54.925
2011-01-01	55.250
2012-01-01	55.150
2013-01-01	54.275
2014-01-01	53.850
2015-01-01	53.425
2016-01-01	53.425
2017-01-01	53.800