Year	Percent
1999-01-01	72.100
2000-01-01	71.700
2001-01-01	72.150
2002-01-01	71.925
2003-01-01	71.950
2004-01-01	72.525
2005-01-01	72.050
2006-01-01	72.425
2007-01-01	72.000
2008-01-01	72.225
2009-01-01	71.500
2010-01-01	70.475
2011-01-01	70.050
2012-01-01	69.250
2013-01-01	68.400
2014-01-01	68.325
2015-01-01	68.475
2016-01-01	70.075
2017-01-01	68.825