Year	Percent
1999-01-01	70.925
2000-01-01	69.525
2001-01-01	69.850
2002-01-01	69.250
2003-01-01	68.000
2004-01-01	71.675
2005-01-01	68.850
2006-01-01	65.650
2007-01-01	62.750
2008-01-01	60.275
2009-01-01	59.475
2010-01-01	57.775
2011-01-01	58.550
2012-01-01	56.900
2013-01-01	54.500
2014-01-01	53.100
2015-01-01	51.450
2016-01-01	48.275
2017-01-01	46.450