Year	Percent
1998-01-01	23.500
1999-01-01	24.425
2000-01-01	24.300
2001-01-01	22.850
2002-01-01	24.025
2003-01-01	25.575
2004-01-01	24.075
2005-01-01	25.850
2006-01-01	26.625
2007-01-01	27.000
2008-01-01	27.550
2009-01-01	27.825
2010-01-01	29.075
2011-01-01	27.450
2012-01-01	26.075
2013-01-01	26.025
2014-01-01	24.975
2015-01-01	24.675
2016-01-01	27.225
2017-01-01	28.025