Year	Percent
1998-01-01	35.500
1999-01-01	33.925
2000-01-01	33.250
2001-01-01	32.975
2002-01-01	33.050
2003-01-01	33.475
2004-01-01	33.725
2005-01-01	33.275
2006-01-01	32.800
2007-01-01	32.475
2008-01-01	32.100
2009-01-01	33.150
2010-01-01	33.625
2011-01-01	33.600
2012-01-01	33.675
2013-01-01	34.225
2014-01-01	34.275
2015-01-01	34.100
2016-01-01	34.350
2017-01-01	33.925