Quarter	Billions of US Dollars
1971-04-01	2.973
1971-07-01	3.184
1971-10-01	3.356
1972-01-01	3.453
1972-04-01	3.333
1972-07-01	3.517
1972-10-01	3.531
1973-01-01	4.049
1973-04-01	4.286
1973-07-01	4.350
1973-10-01	4.390
1974-01-01	4.785
1974-04-01	4.841
1974-07-01	4.971
1974-10-01	5.336
1975-01-01	5.663
1975-04-01	5.303
1975-07-01	5.248
1975-10-01	5.557
1976-01-01	5.314
1976-04-01	5.090
1976-07-01	4.991
1976-10-01	5.345
1977-01-01	5.493
1977-04-01	5.661
1977-07-01	5.979
1977-10-01	6.962
1978-01-01	6.862
1978-04-01	7.159
1978-07-01	8.201
1978-10-01	9.569
1979-01-01	10.060
1979-04-01	10.677
1979-07-01	11.208
1979-10-01	11.973
1980-01-01	11.052
1980-04-01	12.346
1980-07-01	12.769
1980-10-01	12.616
1981-01-01	11.964
1981-04-01	10.868
1981-07-01	11.712
1981-10-01	12.334
1982-01-01	11.422
1982-04-01	11.193
1982-07-01	11.312
1982-10-01	11.399
1983-01-01	10.530
1983-04-01	10.180
1983-07-01	9.866
1983-10-01	9.780
1984-01-01	10.177
1984-04-01	9.770
1984-07-01	9.365
1984-10-01	9.405
1985-01-01	9.580
1985-04-01	9.796
1985-07-01	11.230
1985-10-01	12.424
1986-01-01	12.506
1986-04-01	13.020
1986-07-01	13.109
1986-10-01	13.846
1987-01-01	14.628
1987-04-01	15.103
1987-07-01	15.598
1987-10-01	18.382
1988-01-01	17.658
1988-04-01	16.483
1988-07-01	16.417
1988-10-01	17.572
1989-01-01	16.156
1989-04-01	16.021
1989-07-01	17.110
1989-10-01	19.068
1990-01-01	19.953
1990-04-01	20.446
1990-07-01	23.547
1990-10-01	24.928
1991-01-01	21.251
1991-04-01	20.340
1991-07-01	22.771
1991-10-01	25.512
1992-01-01	22.796
1992-04-01	25.328
1992-07-01	27.164
1992-10-01	24.860
1993-01-01	23.343
1993-04-01	22.289
1993-07-01	22.666
1993-10-01	23.070
1994-01-01	23.677
1994-04-01	26.029
1994-07-01	27.291
1994-10-01	27.905
1995-01-01	29.944
1995-04-01	31.857
1995-07-01	32.310
1995-10-01	33.286
1996-01-01	33.947
1996-04-01	36.042
1996-07-01	37.564
1996-10-01	41.129
1997-01-01	39.988
1997-04-01	42.215
1997-07-01	42.498
1997-10-01	44.653
1998-01-01	45.155
1998-04-01	48.993
1998-07-01	54.768
1998-10-01	57.081
1999-01-01	55.936
1999-04-01	60.735
1999-07-01	65.488
1999-10-01	67.862
2000-01-01	70.427
2000-04-01	71.968
2000-07-01	69.913
2000-10-01	75.765
2001-01-01	74.909
2001-04-01	76.329
2001-07-01	83.583
2001-10-01	83.710
2002-01-01	84.161
2002-04-01	98.084
2002-07-01	102.095
2002-10-01	109.731
2003-01-01	116.354
2003-04-01	126.692
2003-07-01	136.204
2003-10-01	156.951
2004-01-01	162.106
2004-04-01	171.756
2004-07-01	188.160
2004-10-01	221.096
2005-01-01	222.541
2005-04-01	222.543
2005-07-01	237.429
2005-10-01	249.280
2006-01-01	271.975
2006-04-01	304.448
2006-07-01	319.653
2006-10-01	351.044
2007-01-01	367.419
2007-04-01	390.011
2007-07-01	426.053
2007-10-01	457.802
2008-01-01	502.204
2008-04-01	502.260
2008-07-01	463.754
2008-10-01	432.431
2009-01-01	414.514
2009-04-01	433.972
2009-07-01	436.125
2009-10-01	412.620
2010-01-01	372.938
2010-04-01	318.244
2010-07-01	336.602
2010-10-01	297.750
2011-01-01	313.273
2011-04-01	315.601
2011-07-01	293.544
2011-10-01	256.856
2012-01-01	262.050
2012-04-01	244.906
2012-07-01	248.579
2012-10-01	257.698
2013-01-01	247.893
2013-04-01	249.461
2013-07-01	258.446
2013-10-01	258.192
2014-01-01	252.864
2014-04-01	233.459
2014-07-01	203.761
2014-10-01	190.843
2015-01-01	161.164
2015-04-01	163.980
2015-07-01	160.064
2015-10-01	151.389
2016-01-01	153.983
2016-04-01	148.862
2016-07-01	149.804
2016-10-01	137.681
2017-01-01	139.471
2017-04-01	152.107
2017-07-01	157.159
2017-10-01	157.336
2018-01-01	161.344