Year	Percent
2000-01-01	79.900
2001-01-01	79.900
2002-01-01	79.225
2003-01-01	79.300
2004-01-01	79.925
2005-01-01	80.650
2006-01-01	81.675
2007-01-01	84.750
2008-01-01	83.550
2009-01-01	80.650
2010-01-01	78.700
2011-01-01	78.000
2012-01-01	77.825
2013-01-01	78.350
2014-01-01	78.575
2015-01-01	78.975
2016-01-01	79.200
2017-01-01	78.750