Year	Percent
1999-01-01	70.375
2000-01-01	70.275
2001-01-01	69.775
2002-01-01	69.350
2003-01-01	69.500
2004-01-01	66.600
2005-01-01	66.800
2006-01-01	67.625
2007-01-01	68.750
2008-01-01	69.175
2009-01-01	67.875
2010-01-01	68.175
2011-01-01	68.350
2012-01-01	68.150
2013-01-01	67.875
2014-01-01	67.150
2015-01-01	67.350
2016-01-01	67.750
2017-01-01	68.425