Year	Percent
1990-01-01	16.500
1991-01-01	20.000
1992-01-01	18.000
1993-01-01	15.000
1994-01-01	14.000
1995-01-01	16.000
1996-01-01	14.500
1997-01-01	12.500
1998-01-01	12.750
1999-01-01	12.250
2000-01-01	12.250
2001-01-01	11.600
2002-01-01	11.125
2003-01-01	10.750
2004-01-01	10.500
2005-01-01	10.500
2006-01-01	11.250
2007-01-01	13.000
2008-01-01	12.880
2009-01-01	11.500
2010-01-01	8.150
2011-01-01	10.380
2012-01-01	10.130
2013-01-01	10.130
2014-01-01	10.130
2015-01-01	9.500
2016-01-01	9.475
2017-01-01	9.150