Year	Percent
1999-01-01	88.600
2000-01-01	86.500
2001-01-01	84.925
2002-01-01	82.050
2003-01-01	77.650
2004-01-01	74.225
2005-01-01	72.325
2006-01-01	72.325
2007-01-01	73.125
2008-01-01	73.375
2009-01-01	71.925
2010-01-01	68.325
2011-01-01	65.250
2012-01-01	65.500
2013-01-01	65.275
2014-01-01	62.625
2015-01-01	60.100
2016-01-01	56.525
2017-01-01	55.700