Year	Percent
2001-01-01	55.750
2002-01-01	55.800
2003-01-01	55.425
2004-01-01	54.675
2005-01-01	54.450
2006-01-01	54.950
2007-01-01	55.825
2008-01-01	55.850
2009-01-01	54.625
2010-01-01	53.950
2011-01-01	55.050
2012-01-01	55.450
2013-01-01	55.700
2014-01-01	56.225
2015-01-01	56.825
2016-01-01	57.475
2017-01-01	58.075