Year	Percent
1999-01-01	69.475
2000-01-01	69.875
2001-01-01	70.450
2002-01-01	69.850
2003-01-01	70.000
2004-01-01	69.700
2005-01-01	68.950
2006-01-01	68.650
2007-01-01	68.300
2008-01-01	68.825
2009-01-01	68.425
2010-01-01	68.675
2011-01-01	68.700
2012-01-01	69.425
2013-01-01	69.850
2014-01-01	70.275
2015-01-01	70.925
2016-01-01	71.875
2017-01-01	72.100