Year	Percent
1998-01-01	38.575
1999-01-01	39.400
2000-01-01	38.250
2001-01-01	38.975
2002-01-01	42.425
2003-01-01	44.225
2004-01-01	45.075
2005-01-01	46.875
2006-01-01	47.750
2007-01-01	48.250
2008-01-01	49.525
2009-01-01	49.675
2010-01-01	49.725
2011-01-01	50.600
2012-01-01	52.375
2013-01-01	54.800
2014-01-01	56.825
2015-01-01	57.975
2016-01-01	60.850
2017-01-01	63.650