Year	Percent
1980-01-01	3.5000000000000000
1981-01-01	3.5000000000000000
1982-01-01	3.5000000000000000
1983-01-01	3.5000000000000000
1984-01-01	3.5000000000000000
1985-01-01	3.5000000000000000
1986-01-01	3.5000000000000000
1987-01-01	3.5000000000000000
1988-01-01	3.5000000000000000
1989-01-01	3.5000000000000000
1990-01-01	3.5000000000000000
1991-01-01	3.5000000000000000
1992-01-01	3.7500000000000000
1993-01-01	3.0000000000000000
1994-01-01	4.0000000000000000
1995-01-01	4.0000000000000000
1996-01-01	4.0000000000000000
1997-01-01	4.0000000000000000
1998-01-01	4.0000000000000000
1999-01-01	4.0000000000000000
2000-01-01	4.0000000000000000
2001-01-01	4.0000000000000000
2002-01-01	4.0000000000000000
2003-01-01	4.0000000000000000
2004-01-01	3.7900000000000000
2005-01-01	2.5900000000000000
2006-01-01	2.9500000000000000
2007-01-01	2.8000000000000000
2008-01-01	2.8400000000000000
2009-01-01	2.6500000000000000
2010-01-01	5.6000000000000000
2011-01-01	3.3400000000000000
2012-01-01	3.6075699999999995
2013-01-01	3.7946199999999997
2014-01-01	3.1294800000000000
2015-01-01	1.8541200000000000
2016-01-01	1.5516900000000000