Year	Percent
1999-01-01	77.575
2000-01-01	77.375
2001-01-01	76.700
2002-01-01	76.375
2003-01-01	76.375
2004-01-01	73.325
2005-01-01	73.750
2006-01-01	74.950
2007-01-01	76.325
2008-01-01	76.850
2009-01-01	75.525
2010-01-01	75.975
2011-01-01	76.225
2012-01-01	76.225
2013-01-01	76.000
2014-01-01	75.250
2015-01-01	75.150
2016-01-01	75.425
2017-01-01	76.150