Year	Percent
1998-01-01	49.800
1999-01-01	49.525
2000-01-01	49.825
2001-01-01	49.575
2002-01-01	50.450
2003-01-01	51.425
2004-01-01	51.775
2005-01-01	52.325
2006-01-01	53.300
2007-01-01	53.700
2008-01-01	54.300
2009-01-01	53.925
2010-01-01	52.325
2011-01-01	48.675
2012-01-01	44.700
2013-01-01	42.850
2014-01-01	43.375
2015-01-01	44.550
2016-01-01	45.600
2017-01-01	46.750