Year	Percent
1998-01-01	25.675
1999-01-01	25.750
2000-01-01	26.475
2001-01-01	26.300
2002-01-01	25.800
2003-01-01	25.200
2004-01-01	27.700
2005-01-01	25.675
2006-01-01	25.300
2007-01-01	24.550
2008-01-01	24.225
2009-01-01	21.550
2010-01-01	20.250
2011-01-01	19.200
2012-01-01	18.450
2013-01-01	16.275
2014-01-01	15.575
2015-01-01	15.625
2016-01-01	16.550
2017-01-01	17.075