Year	Percent
1977-01-01	6.3382300000000000
1978-01-01	11.9415000000000000
1979-01-01	12.1960000000000000
1980-01-01	11.7665000000000000
1981-01-01	9.3177500000000000
1982-01-01	9.5307400000000000
1983-01-01	13.0284000000000000
1984-01-01	12.9319000000000000
1985-01-01	9.2584500000000000
1986-01-01	6.9847399999999995
1987-01-01	8.8977300000000010
1988-01-01	10.7565000000000000
1989-01-01	8.3066400000000000
1990-01-01	9.9315100000000010
1991-01-01	10.9655000000000000
1992-01-01	14.5833000000000000
1993-01-01	12.1601000000000000
1994-01-01	7.0754199999999990
1995-01-01	5.3624300000000010
1996-01-01	4.5941300000000010
1997-01-01	4.7133600000000000
1998-01-01	3.9727099999999997
1999-01-01	3.5666100000000000
2000-01-01	2.8566100000000000
2001-01-01	2.9820100000000000
2002-01-01	3.2932000000000000
2003-01-01	3.5706000000000000
2004-01-01	4.2370400000000000
2005-01-01	5.5943100000000000
2006-01-01	4.9584100000000000
2007-01-01	5.8674599999999995
2008-01-01	5.3397000000000000
2009-01-01	3.7832100000000000
2010-01-01	5.6892500000000000
2011-01-01	6.0695700000000000
2012-01-01	6.8855699999999995
2013-01-01	6.1794699999999990
2014-01-01	6.4054000000000000
2015-01-01	5.5081200000000000
2016-01-01	5.6166199999999990
2017-01-01	9.5696100000000000