Year	Percent
1980-01-01	4.6336699999999995
1981-01-01	4.1425800000000010
1982-01-01	5.7155200000000000
1983-01-01	8.4579100000000000
1984-01-01	9.4757500000000000
1985-01-01	9.1015199999999990
1986-01-01	11.2472000000000000
1987-01-01	10.6129000000000000
1988-01-01	10.1070000000000010
1989-01-01	10.1655000000000000
1990-01-01	9.0268800000000000
1991-01-01	8.5405199999999990
1992-01-01	6.3909600000000000
1993-01-01	4.9742200000000000
1994-01-01	5.1396300000000000
1995-01-01	3.8523500000000000
1996-01-01	2.3723400000000003
1997-01-01	1.2371400000000000
1998-01-01	0.6151010000000000
1999-01-01	0.6194109999999999
2000-01-01	0.6205729999999999
2001-01-01	0.7633250000000000
2002-01-01	0.9764910000000000
2003-01-01	1.1855100000000000
2004-01-01	1.4629500000000000
2005-01-01	1.5584500000000000
2006-01-01	2.2614799999999997
2007-01-01	2.1069600000000000
2008-01-01	2.2873300000000000
2009-01-01	3.7293100000000000
2010-01-01	3.8887500000000000
2011-01-01	5.5245400000000000
2012-01-01	5.9566400000000000
2013-01-01	7.0187399999999990
2014-01-01	7.3286500000000000
2015-01-01	7.1456899999999990
2016-01-01	6.3106599999999995