Year	Percent
1980-01-01	5.5000000000000000
1981-01-01	5.0000000000000000
1982-01-01	5.0000000000000000
1983-01-01	3.0833300000000000
1984-01-01	3.8333300000000000
1985-01-01	4.4166700000000000
1986-01-01	6.0000000000000000
1987-01-01	5.8333300000000000
1988-01-01	4.8541700000000000
1989-01-01	4.4583300000000000
1990-01-01	4.5833300000000000
1991-01-01	8.2577500000000000
1992-01-01	8.5466600000000010
1993-01-01	8.4787400000000000
1994-01-01	6.2754500000000000
1995-01-01	8.4920600000000000
1996-01-01	8.3607400000000000
1997-01-01	8.1331899999999990
1998-01-01	6.4545300000000000
1999-01-01	8.3065900000000000
2000-01-01	8.1296000000000000
2001-01-01	8.0066200000000000
2002-01-01	8.6491800000000000
2003-01-01	9.1040400000000000
2004-01-01	8.3116000000000000
2005-01-01	8.1387100000000010
2006-01-01	7.4797800000000000
2007-01-01	6.7600000000000000
2008-01-01	7.2029999999999990
2009-01-01	7.5880700000000000
2010-01-01	7.1968500000000000
2011-01-01	7.0164800000000005
2012-01-01	6.1359699999999995
2013-01-01	6.1037600000000000
2014-01-01	6.2070000000000010
2015-01-01	6.5800000000000000
2016-01-01	6.6600000000000000