Quarter	Billions of US Dollars
1971-01-01	0.011
1971-04-01	0.011
1971-07-01	0.012
1971-10-01	0.012
1972-01-01	0.012
1972-04-01	0.038
1972-07-01	0.038
1972-10-01	0.039
1973-01-01	0.070
1973-04-01	0.166
1973-07-01	0.166
1973-10-01	0.160
1974-01-01	0.171
1974-04-01	0.171
1974-07-01	0.169
1974-10-01	0.182
1975-01-01	0.183
1975-04-01	0.183
1975-07-01	0.210
1975-10-01	0.235
1976-01-01	0.239
1976-04-01	0.235
1976-07-01	0.311
1976-10-01	0.426
1977-01-01	0.440
1977-04-01	0.437
1977-07-01	0.511
1977-10-01	0.568
1978-01-01	0.586
1978-04-01	0.585
1978-07-01	0.654
1978-10-01	0.647
1979-01-01	0.662
1979-04-01	0.667
1979-07-01	1.668
1979-10-01	2.191
1980-01-01	1.975
1980-04-01	2.169
1980-07-01	2.116
1980-10-01	2.060
1981-01-01	2.019
1981-04-01	1.841
1981-07-01	1.860
1981-10-01	1.958
1982-01-01	1.891
1982-04-01	1.886
1982-07-01	1.877
1982-10-01	1.990
1983-01-01	2.134
1983-04-01	2.224
1983-07-01	2.239
1983-10-01	2.537
1984-01-01	2.727
1984-04-01	2.684
1984-07-01	3.010
1984-10-01	3.419
1985-01-01	3.863
1985-04-01	4.181
1985-07-01	5.003
1985-10-01	5.308
1986-01-01	6.579
1986-04-01	7.449
1986-07-01	8.410
1986-10-01	8.996
1987-01-01	9.398
1987-04-01	9.414
1987-07-01	9.680
1987-10-01	10.238
1988-01-01	10.140
1988-04-01	9.992
1988-07-01	10.320
1988-10-01	11.235
1989-01-01	10.927
1989-04-01	10.846
1989-07-01	11.385
1989-10-01	11.765
1990-01-01	12.131
1990-04-01	13.525
1990-07-01	13.701
1990-10-01	14.336
1991-01-01	14.561
1991-04-01	14.678
1991-07-01	15.222
1991-10-01	16.327
1992-01-01	15.682
1992-04-01	16.242
1992-07-01	16.570
1992-10-01	15.946
1993-01-01	16.120
1993-04-01	16.506
1993-07-01	16.321
1993-10-01	16.268
1994-01-01	17.058
1994-04-01	17.829
1994-07-01	18.585
1994-10-01	19.847
1995-01-01	22.078
1995-04-01	23.015
1995-07-01	23.051
1995-10-01	22.999
1996-01-01	20.777
1996-04-01	19.290
1996-07-01	19.493
1996-10-01	18.709
1997-01-01	17.782
1997-04-01	18.107
1997-07-01	19.341
1997-10-01	19.711
1998-01-01	18.785
1998-04-01	17.479
1998-07-01	17.836
1998-10-01	17.722
1999-01-01	16.884
1999-04-01	16.179
1999-07-01	16.275
1999-10-01	14.497
2000-01-01	14.309
2000-04-01	13.915
2000-07-01	13.519
2000-10-01	14.333
2001-01-01	17.773
2001-04-01	21.638
2001-07-01	24.050
2001-10-01	23.418
2002-01-01	26.660
2002-04-01	29.303
2002-07-01	29.091
2002-10-01	31.427
2003-01-01	32.978
2003-04-01	35.368
2003-07-01	36.241
2003-10-01	39.988
2004-01-01	39.475
2004-04-01	40.880
2004-07-01	43.150
2004-10-01	47.029
2005-01-01	44.542
2005-04-01	43.329
2005-07-01	41.788
2005-10-01	41.636
2006-01-01	47.740
2006-04-01	51.137
2006-07-01	46.637
2006-10-01	53.538
2007-01-01	58.146
2007-04-01	74.122
2007-07-01	76.901
2007-10-01	83.545
2008-01-01	87.650
2008-04-01	104.399
2008-07-01	93.212
2008-10-01	113.289
2009-01-01	117.957
2009-04-01	144.556
2009-07-01	150.444
2009-10-01	154.627
2010-01-01	152.915
2010-04-01	144.143
2010-07-01	167.256
2010-10-01	161.282
2011-01-01	171.683
2011-04-01	173.789
2011-07-01	156.045
2011-10-01	149.389
2012-01-01	145.801
2012-04-01	141.213
2012-07-01	147.348
2012-10-01	150.136
2013-01-01	146.778
2013-04-01	152.410
2013-07-01	165.772
2013-10-01	172.147
2014-01-01	168.206
2014-04-01	165.450
2014-07-01	153.647
2014-10-01	150.308
2015-01-01	137.100
2015-04-01	144.978