Year	Ratio
1976-01-01	0.268750011920929
1977-01-01	0.291429996490479
1978-01-01	0.255640000104904
1983-01-01	0.258219987154007
1989-01-01	0.258969992399216
1990-01-01	0.308230012655258
1991-01-01	0.322019994258881
2000-01-01	0.373100012540817
2002-01-01	0.245639994740486
2003-01-01	0.298249989748001
2004-01-01	0.352169990539551
2005-01-01	0.538089990615845
2006-01-01	0.516610026359558
2008-01-01	0.603659987449646
2009-01-01	0.597270011901855
2010-01-01	0.614149987697601
2011-01-01	0.631659984588623
2013-01-01	0.824689984321594
2015-01-01	1.021540045738220
2016-01-01	1.070279955863950