Year	Percent
1999-01-01	76.875
2000-01-01	76.175
2001-01-01	76.575
2002-01-01	76.325
2003-01-01	76.750
2004-01-01	76.950
2005-01-01	76.425
2006-01-01	76.450
2007-01-01	76.125
2008-01-01	76.400
2009-01-01	75.325
2010-01-01	74.225
2011-01-01	73.575
2012-01-01	72.625
2013-01-01	71.450
2014-01-01	71.775
2015-01-01	72.275
2016-01-01	73.525
2017-01-01	72.250