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	2.791
2000-04-01	3.129
2000-07-01	3.018
2000-10-01	2.514
2001-01-01	2.343
2001-04-01	2.577
2001-07-01	3.169
2001-10-01	2.531
2002-01-01	2.759
2002-04-01	4.147
2002-07-01	4.179
2002-10-01	4.593
2003-01-01	3.991
2003-04-01	6.287
2003-07-01	8.192
2003-10-01	10.744
2004-01-01	13.791
2004-04-01	15.655
2004-07-01	19.279
2004-10-01	23.618
2005-01-01	26.517
2005-04-01	25.804
2005-07-01	26.801
2005-10-01	27.968
2006-01-01	31.682
2006-04-01	34.366
2006-07-01	37.953
2006-10-01	44.775
2007-01-01	54.041
2007-04-01	58.433
2007-07-01	60.588
2007-10-01	67.171
2008-01-01	76.326
2008-04-01	82.392
2008-07-01	73.322
2008-10-01	67.572
2009-01-01	61.915
2009-04-01	64.375
2009-07-01	66.056
2009-10-01	61.951
2010-01-01	66.347
2010-04-01	100.259
2010-07-01	117.250
2010-10-01	141.351
2011-01-01	148.328
2011-04-01	157.257
2011-07-01	142.533
2011-10-01	147.763
2012-01-01	147.773
2012-04-01	131.474
2012-07-01	115.976
2012-10-01	116.658
2013-01-01	108.756
2013-04-01	108.108
2013-07-01	104.725
2013-10-01	106.069
2014-01-01	105.406
2014-04-01	98.389
2014-07-01	86.872
2014-10-01	86.757
2015-01-01	76.153
2015-04-01	89.281