Year	Percent
1998-01-01	3.375
1999-01-01	3.975
2000-01-01	3.850
2001-01-01	4.225
2002-01-01	4.125
2003-01-01	3.175
2004-01-01	4.425
2005-01-01	3.775
2006-01-01	3.700
2007-01-01	3.400
2008-01-01	3.225
2009-01-01	4.550
2010-01-01	6.225
2011-01-01	8.425
2012-01-01	13.450
2013-01-01	16.225
2014-01-01	17.175
2015-01-01	17.525
2016-01-01	19.175
2017-01-01	18.150