Year	Percent
1980-01-01	4.0000000000000000
1981-01-01	4.7000000000000000
1982-01-01	5.5000000000000000
1983-01-01	2.4166700000000000
1984-01-01	1.6666700000000000
1985-01-01	1.1666700000000000
1986-01-01	6.2083300000000000
1987-01-01	5.0208300000000000
1988-01-01	4.1666700000000000
1989-01-01	5.1666700000000000
1990-01-01	3.6666700000000000
1991-01-01	6.6046300000000000
1992-01-01	7.4802700000000000
1993-01-01	8.7918700000000000
1994-01-01	9.3582700000000000
1995-01-01	8.5272700000000000
1996-01-01	7.8488500000000000
1997-01-01	7.7144600000000010
1998-01-01	7.9068800000000000
1999-01-01	8.0003300000000000
2000-01-01	6.9213000000000000
2001-01-01	7.0627800000000000
2002-01-01	7.0543300000000000
2003-01-01	8.6900000000000000
2004-01-01	7.8105899999999995
2005-01-01	7.2571400000000000
2006-01-01	6.9160400000000000
2007-01-01	7.0900000000000000
2008-01-01	6.8856500000000000
2009-01-01	5.8877900000000000
2010-01-01	7.7225100000000010
2011-01-01	7.6770600000000010
2012-01-01	6.8454300000000000
2013-01-01	7.0520600000000010
2014-01-01	7.0800000000000000
2015-01-01	7.5600000000000000
2016-01-01	7.6900000000000000