Year	Percent
1998-01-01	3.625
1999-01-01	4.250
2000-01-01	4.250
2001-01-01	4.400
2002-01-01	4.750
2003-01-01	3.400
2004-01-01	4.925
2005-01-01	4.675
2006-01-01	5.025
2007-01-01	4.350
2008-01-01	3.950
2009-01-01	5.525
2010-01-01	6.450
2011-01-01	8.075
2012-01-01	13.100
2013-01-01	15.925
2014-01-01	16.350
2015-01-01	16.475
2016-01-01	18.975
2017-01-01	19.675