Quarter	Billions of US Dollars
1987-01-01	1.302
1987-04-01	1.553
1987-07-01	1.468
1987-10-01	1.537
1988-01-01	1.771
1988-04-01	1.645
1988-07-01	1.693
1988-10-01	1.773
1989-01-01	2.165
1989-04-01	2.224
1989-07-01	2.294
1989-10-01	2.653
1990-01-01	2.588
1990-04-01	2.626
1990-07-01	3.340
1990-10-01	3.443
1991-01-01	3.839
1991-04-01	4.117
1991-07-01	4.276
1991-10-01	4.940
1992-01-01	5.171
1992-04-01	5.973
1992-07-01	6.624
1992-10-01	6.791
1993-01-01	8.183
1993-04-01	9.309
1993-07-01	9.639
1993-10-01	10.558
1994-01-01	10.836
1994-04-01	11.205
1994-07-01	11.249
1994-10-01	11.148
1995-01-01	12.181
1995-04-01	12.132
1995-07-01	10.788
1995-10-01	10.085
1996-01-01	9.477
1996-04-01	8.714
1996-07-01	8.633
1996-10-01	8.095
1997-01-01	7.457
1997-04-01	7.296
1997-07-01	6.072
1997-10-01	5.365
1998-01-01	5.285
1998-04-01	4.523
1998-07-01	4.190
1998-10-01	3.731
1999-01-01	2.774
1999-04-01	2.588
1999-07-01	2.909
1999-10-01	3.198
2000-01-01	2.430
2000-04-01	2.424
2000-07-01	2.358
2000-10-01	1.816
2001-01-01	1.688
2001-04-01	1.684
2001-07-01	1.758
2001-10-01	1.622
2002-01-01	1.603
2002-04-01	1.783
2002-07-01	1.763
2002-10-01	1.800
2003-01-01	0.966
2003-04-01	0.824
2003-07-01	1.277
2003-10-01	1.370
2004-01-01	2.259
2004-04-01	2.239
2004-07-01	2.270
2004-10-01	2.949
2005-01-01	2.994
2005-04-01	2.833
2005-07-01	2.081
2005-10-01	1.524
2006-01-01	1.556
2006-04-01	1.625
2006-07-01	1.623
2006-10-01	2.419
2007-01-01	2.670
2007-04-01	2.732
2007-07-01	2.815
2007-10-01	2.870
2008-01-01	2.999
2008-04-01	3.625
2008-07-01	3.331
2008-10-01	7.272
2009-01-01	8.330
2009-04-01	11.059
2009-07-01	10.763
2009-10-01	10.163
2010-01-01	12.844
2010-04-01	53.575
2010-07-01	67.560
2010-10-01	93.422
2011-01-01	103.824
2011-04-01	118.261
2011-07-01	108.788
2011-10-01	116.238
2012-01-01	123.702
2012-04-01	109.151
2012-07-01	101.625
2012-10-01	101.696
2013-01-01	95.715
2013-04-01	93.738
2013-07-01	90.912
2013-10-01	92.429
2014-01-01	92.460
2014-04-01	84.736
2014-07-01	74.711
2014-10-01	74.921
2015-01-01	64.898
2015-04-01	74.952