Year	Percent
1998-01-01	73.675
1999-01-01	73.425
2000-01-01	73.700
2001-01-01	74.200
2002-01-01	74.425
2003-01-01	73.925
2004-01-01	73.350
2005-01-01	73.200
2006-01-01	73.525
2007-01-01	73.475
2008-01-01	73.375
2009-01-01	72.300
2010-01-01	71.800
2011-01-01	71.975
2012-01-01	71.250
2013-01-01	70.250
2014-01-01	69.875
2015-01-01	69.625
2016-01-01	69.875
2017-01-01	70.425