Year	Percent
2000-01-01	82.400
2001-01-01	81.950
2002-01-01	81.475
2003-01-01	81.400
2004-01-01	81.875
2005-01-01	82.575
2006-01-01	81.725
2007-01-01	81.700
2008-01-01	82.475
2009-01-01	83.375
2010-01-01	84.150
2011-01-01	84.225
2012-01-01	84.625
2013-01-01	84.625
2014-01-01	85.100
2015-01-01	85.125
2016-01-01	84.925
2017-01-01	84.925