Year	Ratio
1971-01-01	0.0711600035429001
1972-01-01	0.1546700000762940
1973-01-01	0.1632899940013890
1974-01-01	0.2070499956607820
1975-01-01	0.1779000014066700
1976-01-01	0.1747300028800960
1978-01-01	0.2133799940347670
1979-01-01	0.2117799967527390
1982-01-01	0.2248000055551530
1983-01-01	0.1954800039529800
1984-01-01	0.2188600003719330
1985-01-01	0.2113900035619740
1986-01-01	0.1827699989080430
1987-01-01	0.1830700039863590
1988-01-01	0.1588499993085860
1991-01-01	0.1474799960851670
1992-01-01	0.1821900010108950
1993-01-01	0.1932899951934810
1994-01-01	0.2067199945449830
1995-01-01	0.2068600058555600
1996-01-01	0.2208400070667270
1997-01-01	0.2306099981069560
1999-01-01	0.2454500049352650
2000-01-01	0.2458699941635130
2001-01-01	0.2465000003576280
2006-01-01	0.3236800134181980
2007-01-01	0.3413499891757970
2008-01-01	0.3721899986267090
2009-01-01	0.3907699882984160
2010-01-01	0.3538999855518340
2011-01-01	0.2723200023174290
2012-01-01	0.3450900018215180
2013-01-01	0.3801200091838840
2014-01-01	0.3651199936866760
2015-01-01	0.4019399881362920
2016-01-01	0.4262000024318700