Year	Ratio
1970-01-01	0.0493299998342991
1971-01-01	0.2294699996709820
1972-01-01	0.1634999960660930
1973-01-01	0.1902800053358080
1974-01-01	0.1841299980878830
1975-01-01	0.1571200042963030
1976-01-01	0.2054000049829480
1977-01-01	0.3326100111007690
1978-01-01	0.3582499921321870
1979-01-01	0.3733800053596500
1980-01-01	0.4407100081443790
1981-01-01	0.4126099944114690
1982-01-01	0.3456200063228610
1983-01-01	0.4379000067710880
1984-01-01	0.3927600085735320
1985-01-01	0.6004199981689450
1986-01-01	0.5228099822998050
1987-01-01	0.6459599733352660
1988-01-01	0.5223699808120730
1989-01-01	0.5418000221252440
1990-01-01	0.5957400202751160
1991-01-01	0.7300599813461300
1994-01-01	0.8460800051689150
1995-01-01	0.9986600279808040
1997-01-01	0.8427299857139590
1999-01-01	0.7998700141906740
2000-01-01	0.8542100191116330
2001-01-01	1.2423000335693400
2002-01-01	0.9789299964904790
2003-01-01	0.9220499992370610
2004-01-01	0.9672200083732610
2005-01-01	1.0314199924469000
2006-01-01	1.0067900419235200
2007-01-01	1.1713000535965000
2008-01-01	1.2365299463272100
2009-01-01	1.1920399665832500
2010-01-01	1.2087700366973900
2011-01-01	1.3036400079727200
2012-01-01	1.3277299404144300
2013-01-01	1.2246999740600600
2014-01-01	1.2302299737930300
2015-01-01	1.3124799728393600
2017-01-01	1.2889399528503400