Year	Percent
1998-01-01	40.850
1999-01-01	39.800
2000-01-01	39.000
2001-01-01	36.425
2002-01-01	36.025
2003-01-01	34.375
2004-01-01	36.600
2005-01-01	33.700
2006-01-01	32.175
2007-01-01	30.975
2008-01-01	30.050
2009-01-01	30.650
2010-01-01	30.000
2011-01-01	29.100
2012-01-01	29.125
2013-01-01	28.400
2014-01-01	28.025
2015-01-01	25.975
2016-01-01	24.650
2017-01-01	25.050