Year	Percent
1999-01-01	88.950
2000-01-01	89.275
2001-01-01	89.000
2002-01-01	88.900
2003-01-01	87.575
2004-01-01	85.200
2005-01-01	81.900
2006-01-01	79.100
2007-01-01	76.750
2008-01-01	73.600
2009-01-01	71.050
2010-01-01	67.750
2011-01-01	65.425
2012-01-01	62.000
2013-01-01	59.550
2014-01-01	57.850
2015-01-01	54.200
2016-01-01	51.800
2017-01-01	46.950