Year	Percent
1998-01-01	27.650
1999-01-01	26.150
2000-01-01	25.475
2001-01-01	24.975
2002-01-01	25.050
2003-01-01	25.550
2004-01-01	25.775
2005-01-01	25.275
2006-01-01	24.800
2007-01-01	24.450
2008-01-01	24.025
2009-01-01	25.025
2010-01-01	25.500
2011-01-01	25.025
2012-01-01	24.775
2013-01-01	24.850
2014-01-01	24.625
2015-01-01	24.175
2016-01-01	24.100
2017-01-01	23.250