Quarter	Billions of US Dollars
1971-01-01	0.015
1971-04-01	0.015
1971-07-01	0.015
1971-10-01	0.015
1972-01-01	0.088
1972-04-01	0.088
1972-07-01	0.115
1972-10-01	0.145
1973-01-01	0.207
1973-04-01	0.273
1973-07-01	0.281
1973-10-01	0.263
1974-01-01	0.274
1974-04-01	0.275
1974-07-01	0.282
1974-10-01	0.350
1975-01-01	0.516
1975-04-01	0.713
1975-07-01	0.848
1975-10-01	1.383
1976-01-01	1.899
1976-04-01	2.166
1976-07-01	2.461
1976-10-01	2.798
1977-01-01	3.522
1977-04-01	4.409
1977-07-01	4.691
1977-10-01	5.803
1978-01-01	6.864
1978-04-01	7.577
1978-07-01	8.385
1978-10-01	9.222
1979-01-01	9.704
1979-04-01	10.169
1979-07-01	11.134
1979-10-01	11.284
1980-01-01	10.785
1980-04-01	11.683
1980-07-01	11.417
1980-10-01	10.705
1981-01-01	9.902
1981-04-01	9.131
1981-07-01	9.253
1981-10-01	9.793
1982-01-01	8.803
1982-04-01	8.391
1982-07-01	8.405
1982-10-01	8.677
1983-01-01	8.307
1983-04-01	7.762
1983-07-01	7.722
1983-10-01	7.343
1984-01-01	7.520
1984-04-01	7.066
1984-07-01	6.849
1984-10-01	7.012
1985-01-01	7.050
1985-04-01	7.224
1985-07-01	8.580
1985-10-01	8.147
1986-01-01	8.846
1986-04-01	9.914
1986-07-01	11.733
1986-10-01	12.738
1987-01-01	14.482
1987-04-01	15.372
1987-07-01	15.143
1987-10-01	16.318
1988-01-01	17.156
1988-04-01	17.934
1988-07-01	18.221
1988-10-01	19.003
1989-01-01	19.364
1989-04-01	18.797
1989-07-01	19.088
1989-10-01	19.671
1990-01-01	18.984
1990-04-01	18.995
1990-07-01	19.415
1990-10-01	19.379
1991-01-01	17.713
1991-04-01	17.066
1991-07-01	18.513
1991-10-01	19.355
1992-01-01	19.231
1992-04-01	21.372
1992-07-01	21.655
1992-10-01	19.713
1993-01-01	19.824
1993-04-01	20.502
1993-07-01	20.007
1993-10-01	19.155
1994-01-01	18.866
1994-04-01	19.042
1994-07-01	19.471
1994-10-01	18.829
1995-01-01	19.319
1995-04-01	18.682
1995-07-01	18.310
1995-10-01	18.241
1996-01-01	18.214
1996-04-01	18.550
1996-07-01	17.805
1996-10-01	18.220
1997-01-01	16.784
1997-04-01	16.306
1997-07-01	19.897
1997-10-01	20.545
1998-01-01	21.138
1998-04-01	23.578
1998-07-01	24.519
1998-10-01	26.170
1999-01-01	26.583
1999-04-01	28.227
1999-07-01	29.311
1999-10-01	29.529
2000-01-01	30.665
2000-04-01	33.316
2000-07-01	32.281
2000-10-01	33.409
2001-01-01	34.162
2001-04-01	35.017
2001-07-01	36.555
2001-10-01	37.387
2002-01-01	38.822
2002-04-01	42.904
2002-07-01	41.735
2002-10-01	44.548
2003-01-01	47.210
2003-04-01	49.727
2003-07-01	54.258
2003-10-01	58.987
2004-01-01	60.019
2004-04-01	62.435
2004-07-01	63.722
2004-10-01	70.855
2005-01-01	72.059
2005-04-01	71.359
2005-07-01	71.700
2005-10-01	74.807
2006-01-01	78.104
2006-04-01	89.120
2006-07-01	95.722
2006-10-01	106.025
2007-01-01	112.209
2007-04-01	114.637
2007-07-01	124.054
2007-10-01	132.391
2008-01-01	147.976
2008-04-01	163.591
2008-07-01	155.602
2008-10-01	150.645
2009-01-01	150.724
2009-04-01	164.080
2009-07-01	173.016
2009-10-01	174.494
2010-01-01	175.583
2010-04-01	174.247
2010-07-01	193.404
2010-10-01	194.526
2011-01-01	216.018
2011-04-01	222.338
2011-07-01	216.531
2011-10-01	218.940
2012-01-01	236.490
2012-04-01	240.471
2012-07-01	247.570
2012-10-01	252.484
2013-01-01	251.501
2013-04-01	259.612
2013-07-01	266.606
2013-10-01	274.286
2014-01-01	275.883
2014-04-01	272.293
2014-07-01	257.746
2014-10-01	253.865
2015-01-01	246.130
2015-04-01	241.480