Year	Percent
1998-01-01	93.125
1999-01-01	92.925
2000-01-01	92.525
2001-01-01	92.625
2002-01-01	92.525
2003-01-01	92.400
2004-01-01	92.325
2005-01-01	92.475
2006-01-01	92.900
2007-01-01	92.900
2008-01-01	93.200
2009-01-01	92.500
2010-01-01	92.675
2011-01-01	92.450
2012-01-01	92.150
2013-01-01	91.150
2014-01-01	91.600
2015-01-01	91.750
2016-01-01	91.900
2017-01-01	92.350