Year	Ratio
1984-01-01	0.510100007057190
1985-01-01	0.349900007247925
1987-01-01	0.381000012159348
2000-01-01	0.541750013828278
2001-01-01	0.535780012607574
2002-01-01	0.536159992218018
2004-01-01	0.601170003414154
2005-01-01	0.596090018749237
2009-01-01	0.702629983425140