Year	Percent
1999-01-01	33.725
2000-01-01	33.675
2001-01-01	32.925
2002-01-01	33.600
2003-01-01	34.100
2004-01-01	31.575
2005-01-01	31.100
2006-01-01	31.200
2007-01-01	30.500
2008-01-01	30.950
2009-01-01	31.075
2010-01-01	30.875
2011-01-01	32.400
2012-01-01	32.950
2013-01-01	32.675
2014-01-01	32.375
2015-01-01	32.400
2016-01-01	33.775
2017-01-01	31.775