Year	Percent
1999-01-01	74.150
2000-01-01	72.875
2001-01-01	74.075
2002-01-01	72.300
2003-01-01	71.100
2004-01-01	68.825
2005-01-01	66.725
2006-01-01	66.400
2007-01-01	64.125
2008-01-01	63.900
2009-01-01	62.850
2010-01-01	60.875
2011-01-01	59.675
2012-01-01	58.675
2013-01-01	55.900
2014-01-01	54.925
2015-01-01	53.375
2016-01-01	51.825
2017-01-01	48.725