Quarter	Billions of US Dollars
1987-01-01	2.947
1987-04-01	3.332
1987-07-01	3.450
1987-10-01	4.075
1988-01-01	3.619
1988-04-01	4.121
1988-07-01	4.382
1988-10-01	5.050
1989-01-01	4.966
1989-04-01	4.950
1989-07-01	5.780
1989-10-01	4.984
1990-01-01	4.568
1990-04-01	5.078
1990-07-01	6.378
1990-10-01	6.571
1991-01-01	7.952
1991-04-01	10.041
1991-07-01	9.637
1991-10-01	9.259
1992-01-01	9.391
1992-04-01	9.762
1992-07-01	11.062
1992-10-01	9.243
1993-01-01	6.775
1993-04-01	7.086
1993-07-01	6.152
1993-10-01	6.487
1994-01-01	5.692
1994-04-01	5.137
1994-07-01	4.551
1994-10-01	4.471
1995-01-01	5.034
1995-04-01	3.544
1995-07-01	3.506
1995-10-01	4.259
1996-01-01	3.750
1996-04-01	9.340
1996-07-01	8.374
1996-10-01	7.054
1997-01-01	8.558
1997-04-01	7.183
1997-07-01	8.232
1997-10-01	8.789
1998-01-01	9.479
1998-04-01	8.203
1998-07-01	11.036
1998-10-01	12.278
1999-01-01	11.094
1999-04-01	8.565
1999-07-01	9.323
1999-10-01	9.377
2000-01-01	9.494
2000-04-01	10.318
2000-07-01	11.240
2000-10-01	11.976
2001-01-01	13.326
2001-04-01	13.375
2001-07-01	12.326
2001-10-01	10.592
2002-01-01	12.198
2002-04-01	14.603
2002-07-01	12.279
2002-10-01	15.518
2003-01-01	15.255
2003-04-01	16.266
2003-07-01	19.299
2003-10-01	19.139
2004-01-01	23.513
2004-04-01	26.939
2004-07-01	34.638
2004-10-01	36.889
2005-01-01	41.698
2005-04-01	40.862
2005-07-01	43.348
2005-10-01	33.568
2006-01-01	34.675
2006-04-01	34.554
2006-07-01	28.734
2006-10-01	35.776
2007-01-01	37.006
2007-04-01	49.949
2007-07-01	45.388
2007-10-01	55.815
2008-01-01	70.379
2008-04-01	87.387
2008-07-01	81.768
2008-10-01	78.005
2009-01-01	79.495
2009-04-01	75.847
2009-07-01	65.911
2009-10-01	64.384
2010-01-01	72.042
2010-04-01	76.054
2010-07-01	80.638
2010-10-01	81.120
2011-01-01	103.376
2011-04-01	96.830
2011-07-01	88.688
2011-10-01	83.709
2012-01-01	86.541
2012-04-01	64.841
2012-07-01	72.749
2012-10-01	64.721
2013-01-01	68.598
2013-04-01	69.163
2013-07-01	73.970
2013-10-01	69.897
2014-01-01	82.742
2014-04-01	83.606
2014-07-01	87.920
2014-10-01	75.655
2015-01-01	78.421
2015-04-01	73.812