Year	Percent
1999-01-01	58.925
2000-01-01	59.050
2001-01-01	56.850
2002-01-01	53.725
2003-01-01	51.900
2004-01-01	48.100
2005-01-01	44.925
2006-01-01	44.775
2007-01-01	43.050
2008-01-01	40.150
2009-01-01	41.325
2010-01-01	40.275
2011-01-01	41.225
2012-01-01	39.750
2013-01-01	40.450
2014-01-01	41.150
2015-01-01	41.625
2016-01-01	39.875
2017-01-01	40.000