Year	Percent
1999-01-01	83.150
2000-01-01	81.975
2001-01-01	81.225
2002-01-01	79.875
2003-01-01	78.275
2004-01-01	81.200
2005-01-01	77.550
2006-01-01	74.850
2007-01-01	72.550
2008-01-01	69.925
2009-01-01	68.925
2010-01-01	66.400
2011-01-01	67.000
2012-01-01	65.500
2013-01-01	63.625
2014-01-01	62.525
2015-01-01	59.825
2016-01-01	57.275
2017-01-01	55.575