Year	Percent
2001-01-01	66.875
2002-01-01	68.200
2003-01-01	68.900
2004-01-01	69.725
2005-01-01	69.025
2006-01-01	69.575
2007-01-01	69.425
2008-01-01	69.050
2009-01-01	69.950
2010-01-01	70.250
2011-01-01	72.100
2012-01-01	73.025
2013-01-01	73.350
2014-01-01	74.900
2015-01-01	75.525
2016-01-01	76.850
2017-01-01	77.825