Year	Percent
1998-01-01	36.825
1999-01-01	36.225
2000-01-01	36.175
2001-01-01	36.700
2002-01-01	35.850
2003-01-01	35.050
2004-01-01	33.825
2005-01-01	33.650
2006-01-01	33.350
2007-01-01	33.450
2008-01-01	33.375
2009-01-01	32.550
2010-01-01	32.175
2011-01-01	32.750
2012-01-01	32.550
2013-01-01	32.525
2014-01-01	32.575
2015-01-01	32.175
2016-01-01	31.800
2017-01-01	31.750