Quarter	Billions of US Dollars
1987-01-01	0.013367
1987-04-01	0.008980
1987-07-01	0.008927
1987-10-01	0.010681
1988-01-01	0.009974
1988-04-01	0.009043
1988-07-01	0.008588
1988-10-01	0.009076