Year	Percent
1999-01-01	29.975
2000-01-01	29.575
2001-01-01	29.850
2002-01-01	30.150
2003-01-01	28.975
2004-01-01	29.050
2005-01-01	27.900
2006-01-01	26.850
2007-01-01	26.775
2008-01-01	26.650
2009-01-01	26.425
2010-01-01	25.475
2011-01-01	25.650
2012-01-01	23.525
2013-01-01	22.900
2014-01-01	21.175
2015-01-01	20.400
2016-01-01	20.175
2017-01-01	19.600