Year	Percent
1999-01-01	49.450
2000-01-01	49.775
2001-01-01	49.025
2002-01-01	49.050
2003-01-01	49.750
2004-01-01	49.700
2005-01-01	50.150
2006-01-01	50.650
2007-01-01	50.300
2008-01-01	49.900
2009-01-01	49.850
2010-01-01	50.350
2011-01-01	50.675
2012-01-01	51.675
2013-01-01	52.150
2014-01-01	53.675
2015-01-01	54.750
2016-01-01	55.725
2017-01-01	56.275