Year	Percent
1999-01-01	80.075
2000-01-01	77.125
2001-01-01	75.800
2002-01-01	73.600
2003-01-01	70.225
2004-01-01	67.975
2005-01-01	65.675
2006-01-01	65.475
2007-01-01	66.300
2008-01-01	67.425
2009-01-01	65.900
2010-01-01	63.550
2011-01-01	61.175
2012-01-01	60.525
2013-01-01	58.750
2014-01-01	55.425
2015-01-01	51.900
2016-01-01	47.850
2017-01-01	46.425