Quarter	Billions of US Dollars
1987-01-01	0.5238
1987-04-01	0.5198
1987-07-01	0.5187
1987-10-01	0.5881
1988-01-01	0.5109
1988-04-01	0.4087
1988-07-01	0.3996
1988-10-01	0.4173
1989-01-01	0.4483
1989-04-01	0.4459
1989-07-01	0.4304
1989-10-01	0.2802
1990-01-01	0.2827
1990-04-01	0.2969
1990-07-01	0.2755
1990-10-01	0.3253
1991-01-01	0.2712
1991-04-01	0.3732
1991-07-01	0.3146
1991-10-01	0.4578
1992-01-01	0.3643
1992-04-01	0.4052
1992-07-01	0.4400
1992-10-01	1.1110
1993-01-01	0.7956
1993-04-01	0.8082
1993-07-01	0.7522
1993-10-01	0.6948
1994-01-01	0.7347
1994-04-01	1.0288
1994-07-01	1.0935
1994-10-01	1.0546
1995-01-01	1.3100
1995-04-01	1.3453
1995-07-01	1.7758
1995-10-01	1.6355
1996-01-01	1.7899
1996-04-01	2.1197
1996-07-01	1.7625
1996-10-01	1.0055
1997-01-01	0.9498
1997-04-01	0.9427
1997-07-01	1.0995
1997-10-01	1.1852
1998-01-01	1.1651
1998-04-01	1.1649
1998-07-01	1.5702
1998-10-01	1.5739
1999-01-01	1.5816
1999-04-01	1.4657
1999-07-01	2.4235
1999-10-01	2.0844
2000-01-01	2.7253
2000-04-01	2.7337
2000-07-01	2.2867
2000-10-01	2.8597
2001-01-01	2.8118
2001-04-01	2.8510
2001-07-01	3.6862
2001-10-01	3.0391
2002-01-01	2.7045
2002-04-01	3.2879
2002-07-01	3.2599
2002-10-01	3.4683
2003-01-01	3.5761
2003-04-01	3.6561
2003-07-01	3.4132
2003-10-01	4.2995
2004-01-01	5.2034
2004-04-01	4.7369
2004-07-01	5.1607
2004-10-01	5.1309
2005-01-01	5.4173
2005-04-01	5.5402
2005-07-01	6.3364
2005-10-01	5.5308
2006-01-01	9.2607
2006-04-01	10.1436
2006-07-01	12.7792
2006-10-01	14.4330
2007-01-01	19.8862
2007-04-01	26.7426
2007-07-01	29.6140
2007-10-01	36.9778
2008-01-01	36.1759
2008-04-01	42.3630
2008-07-01	35.1039
2008-10-01	33.6552
2009-01-01	31.4065
2009-04-01	38.1576
2009-07-01	36.6582
2009-10-01	35.8283
2010-01-01	33.2732
2010-04-01	25.1996
2010-07-01	27.3861
2010-10-01	23.8947
2011-01-01	25.0825
2011-04-01	22.9611
2011-07-01	20.7567
2011-10-01	19.9681
2012-01-01	16.7834
2012-04-01	13.0727
2012-07-01	14.4095
2012-10-01	14.5640
2013-01-01	15.6669
2013-04-01	16.0723
2013-07-01	18.2879
2013-10-01	20.4789
2014-01-01	22.5676
2014-04-01	21.0446
2014-07-01	19.6397
2014-10-01	20.5084
2015-01-01	20.0407
2015-04-01	21.1871