Year	Percent
1999-01-01	90.775
2000-01-01	91.350
2001-01-01	90.925
2002-01-01	91.050
2003-01-01	91.125
2004-01-01	88.050
2005-01-01	87.875
2006-01-01	88.375
2007-01-01	88.950
2008-01-01	88.925
2009-01-01	87.375
2010-01-01	87.700
2011-01-01	88.400
2012-01-01	88.250
2013-01-01	87.500
2014-01-01	86.550
2015-01-01	86.600
2016-01-01	86.575
2017-01-01	87.175