Year	Percent
1999-01-01	88.250
2000-01-01	87.850
2001-01-01	87.875
2002-01-01	87.725
2003-01-01	87.775
2004-01-01	88.225
2005-01-01	88.125
2006-01-01	88.875
2007-01-01	88.875
2008-01-01	89.825
2009-01-01	89.325
2010-01-01	88.675
2011-01-01	88.175
2012-01-01	87.775
2013-01-01	87.500
2014-01-01	87.100
2015-01-01	87.150
2016-01-01	87.350
2017-01-01	86.150