Quarter	Billions of US Dollars
1987-01-01	2.352
1987-04-01	2.504
1987-07-01	2.830
1987-10-01	2.943
1988-01-01	3.151
1988-04-01	4.050
1988-07-01	4.528
1988-10-01	4.513
1989-01-01	5.471
1989-04-01	5.883
1989-07-01	6.468
1989-10-01	6.843
1990-01-01	8.377
1990-04-01	8.618
1990-07-01	10.219
1990-10-01	10.232
1991-01-01	9.944
1991-04-01	9.233
1991-07-01	9.842
1991-10-01	9.162
1992-01-01	8.489
1992-04-01	9.409
1992-07-01	10.044
1992-10-01	8.940
1993-01-01	8.736
1993-04-01	8.711
1993-07-01	9.515
1993-10-01	10.624
1994-01-01	11.249
1994-04-01	11.315
1994-07-01	12.326
1994-10-01	12.780
1995-01-01	12.598
1995-04-01	12.116
1995-07-01	11.727
1995-10-01	11.887
1996-01-01	12.533
1996-04-01	12.809
1996-07-01	13.158
1996-10-01	12.836
1997-01-01	13.756
1997-04-01	14.026
1997-07-01	14.320
1997-10-01	14.963
1998-01-01	14.682
1998-04-01	15.657
1998-07-01	16.681
1998-10-01	16.316
1999-01-01	16.206
1999-04-01	18.808
1999-07-01	20.467
1999-10-01	20.025
2000-01-01	21.979
2000-04-01	21.369
2000-07-01	19.712
2000-10-01	20.905
2001-01-01	22.027
2001-04-01	21.328
2001-07-01	22.241
2001-10-01	21.130
2002-01-01	20.834
2002-04-01	24.151
2002-07-01	26.231
2002-10-01	25.722
2003-01-01	29.504
2003-04-01	31.485
2003-07-01	30.743
2003-10-01	33.676
2004-01-01	38.480
2004-04-01	39.344
2004-07-01	40.977
2004-10-01	45.453
2005-01-01	47.654
2005-04-01	52.213
2005-07-01	54.886
2005-10-01	52.653
2006-01-01	61.128
2006-04-01	63.862
2006-07-01	61.848
2006-10-01	73.469
2007-01-01	86.199
2007-04-01	96.936
2007-07-01	100.637
2007-10-01	107.098
2008-01-01	118.046
2008-04-01	139.318
2008-07-01	144.183
2008-10-01	131.610
2009-01-01	135.290
2009-04-01	158.234
2009-07-01	172.024
2009-10-01	172.257
2010-01-01	186.387
2010-04-01	172.534
2010-07-01	187.026
2010-10-01	182.931
2011-01-01	197.532
2011-04-01	204.309
2011-07-01	202.354
2011-10-01	193.285
2012-01-01	211.538
2012-04-01	208.570
2012-07-01	218.200
2012-10-01	215.519
2013-01-01	209.712
2013-04-01	215.750
2013-07-01	233.175
2013-10-01	226.219
2014-01-01	226.375
2014-04-01	227.881
2014-07-01	216.149
2014-10-01	204.928
2015-01-01	194.822
2015-04-01	203.261