Year	Percent
1999-01-01	81.800
2000-01-01	82.625
2001-01-01	82.750
2002-01-01	83.600
2003-01-01	84.025
2004-01-01	81.425
2005-01-01	81.550
2006-01-01	82.175
2007-01-01	82.875
2008-01-01	83.400
2009-01-01	82.875
2010-01-01	83.325
2011-01-01	84.100
2012-01-01	84.325
2013-01-01	84.000
2014-01-01	83.450
2015-01-01	83.475
2016-01-01	83.575
2017-01-01	84.100