Year	Percent
1980-01-01	5.5000000000000000
1981-01-01	5.5000000000000000
1982-01-01	4.5000000000000000
1983-01-01	4.2083300000000000
1984-01-01	6.0000000000000000
1985-01-01	5.9583300000000000
1986-01-01	6.6250000000000000
1987-01-01	6.6458300000000000
1988-01-01	6.0416700000000000
1989-01-01	7.0000000000000000
1990-01-01	8.0000000000000000
1991-01-01	7.2136200000000000
1992-01-01	7.4852800000000000
1993-01-01	8.0719200000000000
1994-01-01	7.8039800000000000
1995-01-01	6.2884199999999995
1996-01-01	7.0931600000000010
1997-01-01	7.0986500000000000
1998-01-01	7.0209100000000010
1999-01-01	7.0022199999999994
2000-01-01	7.0012200000000000
2001-01-01	7.3428600000000010
2002-01-01	7.1754200000000000
2003-01-01	7.4369300000000000
2004-01-01	5.9678800000000000
2005-01-01	6.7827899999999990
2006-01-01	7.0191100000000000
2007-01-01	6.8000000000000000
2008-01-01	6.8633899999999990
2009-01-01	6.2481900000000000
2010-01-01	6.3191800000000000
2011-01-01	6.2258600000000000
2012-01-01	6.6055300000000000
2013-01-01	6.7428200000000000
2014-01-01	6.7500000000000000
2015-01-01	7.2900000000000000
2016-01-01	7.0400000000000000