Quarter	Billions of US Dollars
1971-01-01	0.025
1972-10-01	0.053
1973-01-01	0.030
1973-04-01	0.020
1973-07-01	0.072
1974-01-01	0.023
1974-04-01	0.059
1974-07-01	0.016
1974-10-01	0.036
1975-04-01	0.034
1975-10-01	0.038
1976-07-01	0.020
1977-01-01	0.030
1977-07-01	0.057
1978-04-01	0.083
1979-04-01	0.039
1979-07-01	0.031
1979-10-01	0.110
1980-01-01	0.116
1980-07-01	0.061
1980-10-01	0.147
1981-01-01	0.100
1981-04-01	0.100
1981-10-01	0.342
1982-01-01	0.300
1982-04-01	0.128
1982-07-01	0.165
1982-10-01	0.143
1983-01-01	0.182
1983-04-01	0.105
1983-07-01	0.057
1983-10-01	0.650
1984-01-01	0.137
1984-04-01	0.091
1984-07-01	0.349
1984-10-01	0.258
1985-01-01	0.509
1985-04-01	0.352
1985-07-01	0.338
1985-10-01	0.285
1986-01-01	0.388
1986-04-01	0.610
1986-07-01	0.928
1986-10-01	0.270
1987-01-01	0.113
1987-04-01	0.268
1987-07-01	0.027
1987-10-01	0.297
1988-01-01	0.392
1988-04-01	0.121
1988-07-01	0.161
1989-01-01	0.277
1989-04-01	0.262
1989-07-01	1.475
1989-10-01	0.296
1990-01-01	0.776
1990-04-01	0.297
1990-07-01	0.206
1990-10-01	0.152
1991-01-01	0.341
1991-04-01	0.642
1991-07-01	0.420
1991-10-01	0.200
1992-01-01	0.552
1992-07-01	0.581
1992-10-01	1.501
1993-01-01	1.531
1993-04-01	0.069
1993-07-01	0.150
1993-10-01	0.387
1994-01-01	0.099
1994-04-01	0.487
1994-07-01	0.267
1994-10-01	0.666
1995-01-01	1.116
1995-04-01	0.898
1995-07-01	1.396
1995-10-01	2.815
1996-01-01	1.596
1996-04-01	2.664
1996-07-01	3.864
1996-10-01	3.235
1997-01-01	5.936
1997-04-01	1.529
1997-07-01	2.730
1997-10-01	2.853
1998-01-01	1.604
1998-04-01	2.746
1998-07-01	1.865
1998-10-01	0.933
1999-01-01	2.741
1999-04-01	2.437
1999-07-01	6.110
1999-10-01	2.786
2000-01-01	3.235
2000-04-01	3.679
2000-07-01	3.107
2000-10-01	2.896
2001-01-01	7.737
2001-04-01	5.672
2001-07-01	2.442
2001-10-01	6.120
2002-01-01	5.238
2002-04-01	4.476
2002-07-01	6.311
2002-10-01	10.120
2003-01-01	12.051
2003-04-01	16.493
2003-07-01	16.680
2003-10-01	32.415
2004-01-01	23.778
2004-04-01	25.301
2004-07-01	28.666
2004-10-01	34.530
2005-01-01	38.071
2005-04-01	52.812
2005-07-01	28.222
2005-10-01	53.090
2006-01-01	52.803
2006-04-01	74.131
2006-07-01	83.470
2006-10-01	87.158
2007-01-01	77.887
2007-04-01	104.787
2007-07-01	77.081
2007-10-01	54.199
2008-01-01	61.503
2008-04-01	68.408
2008-07-01	39.359
2008-10-01	104.866
2009-01-01	58.854
2009-04-01	62.526
2009-07-01	65.673
2009-10-01	31.580
2010-01-01	55.275
2010-04-01	19.663
2010-07-01	32.802
2010-10-01	29.288
2011-01-01	14.784
2011-04-01	20.568
2011-07-01	11.927
2011-10-01	11.347
2012-01-01	24.483
2012-04-01	20.046
2012-07-01	18.390
2012-10-01	35.035
2013-01-01	32.001
2013-04-01	24.226
2013-07-01	22.568
2013-10-01	26.562
2014-01-01	21.691
2014-04-01	26.098
2014-07-01	21.838
2014-10-01	13.798
2015-01-01	24.483
2015-04-01	53.065