Year	Percent
1980-01-01	8.3125000000000000
1981-01-01	8.2500000000000000
1982-01-01	8.2500000000000000
1983-01-01	7.0000000000000000
1984-01-01	7.2500000000000000
1985-01-01	7.2500000000000000
1986-01-01	7.4166700000000000
1987-01-01	8.2500000000000000
1988-01-01	9.2500000000000000
1989-01-01	9.5833300000000000
1990-01-01	9.0000000000000000
1991-01-01	9.0000000000000000
1992-01-01	9.7500000000000000
1993-01-01	9.7500000000000000
1994-01-01	9.7500000000000000
1995-01-01	9.7500000000000000
1996-01-01	9.7500000000000000
1997-01-01	9.7500000000000000
1998-01-01	9.7500000000000000
1999-01-01	9.7500000000000000
2000-01-01	9.7500000000000000
2001-01-01	9.7500000000000000
2002-01-01	9.7500000000000000
2003-01-01	9.7500000000000000
2004-01-01	9.7500000000000000
2005-01-01	1.1483299999999999
2006-01-01	4.8400000000000000
2007-01-01	4.8400000000000000
2008-01-01	4.8000000000000000
2009-01-01	5.3100000000000000
2010-01-01	4.6300000000000000
2011-01-01	4.3500000000000000
2012-01-01	4.0400000000000000
2013-01-01	3.5400000000000000
2014-01-01	2.9800000000000000
2015-01-01	2.1400000000000000