Year	Percent
1999-01-01	87.575
2000-01-01	88.400
2001-01-01	88.950
2002-01-01	88.650
2003-01-01	89.475
2004-01-01	88.925
2005-01-01	87.975
2006-01-01	87.625
2007-01-01	86.900
2008-01-01	87.800
2009-01-01	87.200
2010-01-01	86.950
2011-01-01	87.025
2012-01-01	87.125
2013-01-01	87.200
2014-01-01	87.325
2015-01-01	87.300
2016-01-01	87.600
2017-01-01	86.575