Year	Percent
1999-01-01	88.675
2000-01-01	88.500
2001-01-01	88.175
2002-01-01	88.375
2003-01-01	87.900
2004-01-01	87.575
2005-01-01	88.350
2006-01-01	90.050
2007-01-01	89.825
2008-01-01	90.975
2009-01-01	86.875
2010-01-01	85.350
2011-01-01	85.725
2012-01-01	84.625
2013-01-01	84.975
2014-01-01	85.475
2015-01-01	85.925
2016-01-01	86.450
2017-01-01	85.175