Year	Ratio
1972-01-01	0.558300018310547
1973-01-01	0.605910003185272
1977-01-01	0.901780009269714
1979-01-01	0.970700025558472
1992-01-01	1.225250005722050
1993-01-01	1.339849948883060
1995-01-01	1.579699993133540
1998-01-01	1.558359980583190
2007-01-01	1.370900034904480
2011-01-01	1.343940019607540
2012-01-01	1.227990031242370
2017-01-01	1.465319991111760