Year	Percent
1999-01-01	31.700
2000-01-01	31.800
2001-01-01	31.200
2002-01-01	31.775
2003-01-01	31.725
2004-01-01	31.650
2005-01-01	31.625
2006-01-01	31.750
2007-01-01	32.225
2008-01-01	31.725
2009-01-01	31.875
2010-01-01	32.150
2011-01-01	31.950
2012-01-01	31.650
2013-01-01	31.875
2014-01-01	31.775
2015-01-01	32.125
2016-01-01	31.900
2017-01-01	32.275