Year	Percent
1998-01-01	3.250
1999-01-01	3.800
2000-01-01	3.625
2001-01-01	4.125
2002-01-01	3.875
2003-01-01	3.100
2004-01-01	4.225
2005-01-01	3.325
2006-01-01	3.075
2007-01-01	2.925
2008-01-01	2.875
2009-01-01	4.075
2010-01-01	6.100
2011-01-01	8.625
2012-01-01	13.650
2013-01-01	16.400
2014-01-01	17.675
2015-01-01	18.150
2016-01-01	19.275
2017-01-01	17.150