Year	Percent
1971-01-01	4.50
1972-01-01	7.50
1973-01-01	13.00
1974-01-01	12.00
1975-01-01	11.00
1976-01-01	14.00
1977-01-01	7.17
1978-01-01	12.50
1979-01-01	17.00
1980-01-01	14.00
1981-01-01	14.57
1982-01-01	10.06
1983-01-01	9.00
1984-01-01	9.56
1985-01-01	11.50
1986-01-01	11.00
1987-01-01	8.57
1988-01-01	13.00
1989-01-01	15.00
1990-01-01	14.00
1991-01-01	10.50
1992-01-01	7.00
1993-01-01	5.50
1994-01-01	6.15
1995-01-01	6.61
1996-01-01	6.00
1997-01-01	7.25
1998-01-01	6.42
1999-01-01	5.50
2000-01-01	6.00
2001-01-01	4.00
2002-01-01	4.00
2003-01-01	3.75
2004-01-01	4.75
2005-01-01	4.50
2006-01-01	5.00
2007-01-01	5.54
2008-01-01	2.14
2009-01-01	0.50
2010-01-01	0.50
2011-01-01	0.50
2012-01-01	0.50
2013-01-01	0.50
2014-01-01	0.50