Year	Percent
1998-01-01	7.550
1999-01-01	8.200
2000-01-01	7.625
2001-01-01	7.350
2002-01-01	6.900
2003-01-01	6.350
2004-01-01	6.750
2005-01-01	6.350
2006-01-01	5.800
2007-01-01	5.325
2008-01-01	5.200
2009-01-01	7.100
2010-01-01	10.200
2011-01-01	15.375
2012-01-01	21.825
2013-01-01	24.675
2014-01-01	23.775
2015-01-01	21.875
2016-01-01	19.950
2017-01-01	17.950