Year	Percent
1999-01-01	70.550
2000-01-01	69.825
2001-01-01	70.675
2002-01-01	70.575
2003-01-01	71.525
2004-01-01	69.300
2005-01-01	69.150
2006-01-01	70.250
2007-01-01	70.925
2008-01-01	73.725
2009-01-01	71.225
2010-01-01	70.075
2011-01-01	70.350
2012-01-01	69.550
2013-01-01	69.600
2014-01-01	70.225
2015-01-01	70.950
2016-01-01	73.450
2017-01-01	73.450