Year	Percent
1966-01-01	0.8505850000000000
1967-01-01	0.7807600000000000
1968-01-01	0.7633920000000000
1969-01-01	0.5557270000000001
1970-01-01	0.3459400000000000
1971-01-01	0.6505880000000000
1972-01-01	0.8112760000000000
1973-01-01	0.8544530000000000
1974-01-01	1.2577399999999999
1975-01-01	2.3412800000000000
1976-01-01	2.4334800000000000
1977-01-01	1.9550000000000000
1978-01-01	2.4706700000000000
1979-01-01	2.6035300000000000
1980-01-01	2.9700700000000000
1981-01-01	4.2039300000000010
1982-01-01	6.7762100000000010
1983-01-01	7.0598000000000000
1984-01-01	5.6053400000000000
1985-01-01	5.6822300000000010
1986-01-01	5.8565000000000000
1987-01-01	6.8288500000000000
1988-01-01	7.0935700000000000
1989-01-01	5.9456200000000000
1990-01-01	6.0438600000000000
1991-01-01	7.3272200000000000
1992-01-01	6.1164300000000000
1993-01-01	6.9219100000000005
1994-01-01	10.3724000000000000
1995-01-01	12.4874000000000000
1996-01-01	10.4506000000000000
1997-01-01	6.3309000000000000
1998-01-01	5.0514000000000000
1999-01-01	4.3497600000000000
2000-01-01	3.7142699999999995
2001-01-01	3.5445699999999998
2002-01-01	3.7995000000000000
2003-01-01	3.7370200000000000
2004-01-01	3.5511500000000000
2005-01-01	3.2657500000000000
2006-01-01	2.7845200000000000
2007-01-01	2.1567400000000000
2008-01-01	1.9839600000000000
2009-01-01	2.0347900000000000
2010-01-01	2.1273400000000002
2011-01-01	1.8433000000000000
2012-01-01	1.4101600000000000
2013-01-01	1.3201600000000000
2014-01-01	1.2109100000000000
2015-01-01	1.1007400000000000
2016-01-01	0.9376120000000001