Quarter	Billions of US Dollars
1971-01-01	0.043
1971-04-01	0.072
1971-07-01	0.105
1971-10-01	0.107
1972-01-01	0.110
1972-04-01	0.142
1972-07-01	0.140
1972-10-01	0.140
1973-01-01	0.156
1973-04-01	0.196
1973-07-01	0.197
1973-10-01	0.188
1974-01-01	0.231
1974-04-01	0.311
1974-07-01	0.305
1974-10-01	0.485
1975-01-01	0.906
1975-04-01	1.312
1975-07-01	1.443
1975-10-01	1.905
1976-01-01	2.706
1976-04-01	3.442
1976-07-01	3.696
1976-10-01	4.134
1977-01-01	4.645
1977-04-01	5.269
1977-07-01	5.687
1977-10-01	6.399
1978-01-01	7.054
1978-04-01	7.698
1978-07-01	9.174
1978-10-01	9.963
1979-01-01	11.019
1979-04-01	12.200
1979-07-01	13.773
1979-10-01	13.882
1980-01-01	12.963
1980-04-01	14.490
1980-07-01	14.993
1980-10-01	15.293
1981-01-01	14.839
1981-04-01	14.671
1981-07-01	16.553
1981-10-01	18.167
1982-01-01	18.453
1982-04-01	18.398
1982-07-01	18.881
1982-10-01	21.380
1983-01-01	22.929
1983-04-01	24.724
1983-07-01	25.778
1983-10-01	27.221
1984-01-01	30.839
1984-04-01	31.372
1984-07-01	32.817
1984-10-01	33.864
1985-01-01	38.005
1985-04-01	41.133
1985-07-01	49.125
1985-10-01	54.076
1986-01-01	60.165
1986-04-01	69.191
1986-07-01	79.270
1986-10-01	86.580
1987-01-01	96.142
1987-04-01	105.218
1987-07-01	118.576
1987-10-01	133.957
1988-01-01	135.207
1988-04-01	136.594
1988-07-01	149.407
1988-10-01	159.400
1989-01-01	171.204
1989-04-01	197.988
1989-07-01	215.034
1989-10-01	236.578
1990-01-01	245.554
1990-04-01	249.787
1990-07-01	268.444
1990-10-01	279.723
1991-01-01	276.173
1991-04-01	282.104
1991-07-01	300.996
1991-10-01	318.649
1992-01-01	310.252
1992-04-01	318.913
1992-07-01	320.484
1992-10-01	308.330
1993-01-01	297.282
1993-04-01	284.379
1993-07-01	276.418
1993-10-01	265.130
1994-01-01	272.518
1994-04-01	272.824
1994-07-01	267.750
1994-10-01	256.448
1995-01-01	269.494
1995-04-01	267.784
1995-07-01	237.897
1995-10-01	230.052
1996-01-01	222.172
1996-04-01	214.771
1996-07-01	209.511
1996-10-01	196.992
1997-01-01	182.357
1997-04-01	181.103
1997-07-01	169.346
1997-10-01	154.479
1998-01-01	142.076
1998-04-01	129.882
1998-07-01	127.965
1998-10-01	132.231
1999-01-01	126.257
1999-04-01	124.387
1999-07-01	130.055
1999-10-01	123.666
2000-01-01	112.963
2000-04-01	112.254
2000-07-01	108.318
2000-10-01	103.976
2001-01-01	97.201
2001-04-01	97.023
2001-07-01	96.968
2001-10-01	94.120
2002-01-01	95.074
2002-04-01	105.536
2002-07-01	102.795
2002-10-01	102.120
2003-01-01	101.654
2003-04-01	103.910
2003-07-01	105.584
2003-10-01	117.097
2004-01-01	122.289
2004-04-01	128.025
2004-07-01	127.577
2004-10-01	136.841
2005-01-01	136.857
2005-04-01	135.735
2005-07-01	139.653
2005-10-01	136.387
2006-01-01	140.800
2006-04-01	145.567
2006-07-01	143.396
2006-10-01	146.916
2007-01-01	146.814
2007-04-01	146.267
2007-07-01	154.135
2007-10-01	160.122
2008-01-01	174.636
2008-04-01	171.937
2008-07-01	169.812
2008-10-01	179.345
2009-01-01	164.123
2009-04-01	162.361
2009-07-01	168.536
2009-10-01	164.801
2010-01-01	165.809
2010-04-01	162.991
2010-07-01	177.751
2010-10-01	178.862
2011-01-01	180.169
2011-04-01	175.282
2011-07-01	177.882
2011-10-01	175.267
2012-01-01	177.790
2012-04-01	175.465
2012-07-01	187.383
2012-10-01	180.374
2013-01-01	182.149
2013-04-01	183.275
2013-07-01	202.382
2013-10-01	201.232
2014-01-01	208.932
2014-04-01	222.177
2014-07-01	229.408
2014-10-01	230.899
2015-01-01	237.600
2015-04-01	236.479