Year	Percent
1999-01-01	32.425
2000-01-01	32.150
2001-01-01	32.750
2002-01-01	32.900
2003-01-01	32.400
2004-01-01	32.750
2005-01-01	32.075
2006-01-01	31.100
2007-01-01	31.350
2008-01-01	32.025
2009-01-01	32.275
2010-01-01	32.225
2011-01-01	31.625
2012-01-01	30.425
2013-01-01	29.000
2014-01-01	26.575
2015-01-01	24.725
2016-01-01	23.050
2017-01-01	21.750