Year	Percent
1960-01-01	0.1156069364161850
1961-01-01	0.0000000000000000
1962-01-01	0.1109877913429520
1963-01-01	0.1086956521739130
1964-01-01	0.1055966209081310
1965-01-01	0.1020408163265310
1966-01-01	0.0985221674876847
1967-01-01	0.0959692898272553
1968-01-01	0.7759456838021340
1969-01-01	0.2859866539561490
1970-01-01	0.0926784059314180
1971-01-01	0.1829826166514180
1972-01-01	0.4508566275924260
1973-01-01	0.1746724890829690
1974-01-01	0.0838222967309304
1975-01-01	0.2465078060805260
1976-01-01	0.3228410008071020
1977-01-01	0.3179650238473770
1978-01-01	1.6574585635359100
1979-01-01	1.9425019425019400
1980-01-01	2.2428460943542200
1981-01-01	3.6015325670498100
1982-01-01	3.5364936042136900
1983-01-01	5.6631892697466500
1984-01-01	5.7437407952871900
1985-01-01	4.1816870944484500
1986-01-01	4.1750000000000000
1987-01-01	4.2250000000000000
1988-01-01	5.8000000000000000
1989-01-01	7.2750000000000000
1990-01-01	7.9750000000000000
1991-01-01	10.6000000000000000
1992-01-01	10.6500000000000000
1993-01-01	9.8000000000000000
1994-01-01	8.3500000000000000
1995-01-01	6.4500000000000000
1996-01-01	6.3000000000000000
1997-01-01	6.8250000000000000
1998-01-01	7.7250000000000000
1999-01-01	7.0250000000000000
2000-01-01	6.1500000000000000
2001-01-01	5.4500000000000000
2002-01-01	5.3000000000000000
2003-01-01	4.7750000000000000
2004-01-01	4.0250000000000000
2005-01-01	3.8250000000000000
2006-01-01	3.8500000000000000
2007-01-01	3.5750000000000000
2008-01-01	4.0250000000000000
2009-01-01	5.8250000000000000
2010-01-01	6.1500000000000000
2011-01-01	5.9500000000000000
2012-01-01	6.4000000000000000
2013-01-01	5.7500000000000000
2014-01-01	5.3750000000000000
2015-01-01	5.3500000000000000
2016-01-01	5.1000000000000000
2017-01-01	4.7000000000000000