Quarter	Billions of US Dollars
1987-01-01	0.1945
1987-04-01	0.2250
1987-07-01	0.3715
1987-10-01	0.4556
1988-01-01	0.7560
1988-04-01	0.3618
1988-07-01	0.3876
1988-10-01	0.4146
1989-01-01	0.2358
1989-04-01	0.2262
1989-07-01	0.3060
1989-10-01	0.4056
1990-01-01	0.4306
1990-04-01	0.5970
1990-07-01	0.7181
1990-10-01	2.3527
1991-01-01	0.7909
1991-04-01	0.2704
1991-07-01	0.4507
1991-10-01	0.6469
1992-01-01	0.4914
1992-04-01	0.5312
1992-07-01	0.4848
1992-10-01	1.6540
1993-01-01	1.3428
1993-04-01	1.4652
1993-07-01	0.4021
1993-10-01	0.4713
1994-01-01	0.4942
1994-04-01	0.5466
1994-07-01	0.6773
1994-10-01	0.9122
1995-01-01	1.5214
1995-04-01	1.6697
1995-07-01	1.9591
1995-10-01	2.1693
1996-01-01	2.2145
1996-04-01	2.6985
1996-07-01	3.0135
1996-10-01	3.1888
1997-01-01	3.0471
1997-04-01	3.1330
1997-07-01	3.3893
1997-10-01	4.0263
1998-01-01	4.0061
1998-04-01	3.5845
1998-07-01	4.7189
1998-10-01	4.9133
1999-01-01	4.3153
1999-04-01	4.4095
1999-07-01	5.1739
1999-10-01	5.7542
2000-01-01	4.6512
2000-04-01	5.5135
2000-07-01	6.6537
2000-10-01	6.6388
2001-01-01	7.0677
2001-04-01	8.3518
2001-07-01	9.4052
2001-10-01	8.0458
2002-01-01	8.5631
2002-04-01	10.6628
2002-07-01	7.9793
2002-10-01	9.6995
2003-01-01	9.2698
2003-04-01	8.8795
2003-07-01	9.1459
2003-10-01	10.8301
2004-01-01	9.7017
2004-04-01	9.7155
2004-07-01	9.2926
2004-10-01	10.3844
2005-01-01	9.7940
2005-04-01	9.5716
2005-07-01	9.7933
2005-10-01	9.2004
2006-01-01	10.3989
2006-04-01	11.3651
2006-07-01	10.5172
2006-10-01	11.1007
2007-01-01	10.9036
2007-04-01	10.8648
2007-07-01	12.9782
2007-10-01	12.3494
2008-01-01	11.0818
2008-04-01	11.3964
2008-07-01	9.8131
2008-10-01	9.1123
2009-01-01	7.3339
2009-04-01	7.1637
2009-07-01	6.4653
2009-10-01	7.8023
2010-01-01	9.8918
2010-04-01	8.6217
2010-07-01	9.0928
2010-10-01	8.1637
2011-01-01	8.4200
2011-04-01	9.7006
2011-07-01	9.5982
2011-10-01	10.1438
2012-01-01	10.3327
2012-04-01	9.8847
2012-07-01	9.2565
2012-10-01	9.9641
2013-01-01	9.9180
2013-04-01	8.3574
2013-07-01	7.6749
2013-10-01	6.9046
2014-01-01	6.3604
2014-04-01	8.9545
2014-07-01	8.7571
2014-10-01	7.0317
2015-01-01	7.5803
2015-04-01	6.7692