Year	Percent
1999-01-01	42.500
2000-01-01	42.350
2001-01-01	41.975
2002-01-01	42.575
2003-01-01	43.450
2004-01-01	41.025
2005-01-01	40.775
2006-01-01	40.700
2007-01-01	40.300
2008-01-01	40.500
2009-01-01	40.575
2010-01-01	40.850
2011-01-01	42.075
2012-01-01	42.475
2013-01-01	42.775
2014-01-01	42.350
2015-01-01	42.700
2016-01-01	43.400
2017-01-01	41.550