Year	Percent
1999-01-01	83.200
2000-01-01	82.875
2001-01-01	84.125
2002-01-01	81.775
2003-01-01	80.775
2004-01-01	77.875
2005-01-01	76.625
2006-01-01	75.375
2007-01-01	72.550
2008-01-01	72.150
2009-01-01	70.725
2010-01-01	69.125
2011-01-01	67.025
2012-01-01	65.075
2013-01-01	62.150
2014-01-01	61.025
2015-01-01	58.800
2016-01-01	57.250
2017-01-01	54.250