Quarter	Billions of US Dollars
1971-10-01	0.031
1972-01-01	0.113
1972-04-01	0.153
1972-07-01	0.204
1972-10-01	0.349
1973-01-01	0.456
1973-04-01	0.499
1973-07-01	0.575
1973-10-01	0.669
1974-01-01	0.683
1974-04-01	0.679
1974-07-01	0.671
1974-10-01	0.757
1975-01-01	0.930
1975-04-01	1.075
1975-07-01	1.102
1975-10-01	1.165
1976-01-01	1.235
1976-04-01	1.428
1976-07-01	1.578
1976-10-01	1.860
1977-01-01	2.178
1977-04-01	2.816
1977-07-01	3.754
1977-10-01	4.871
1978-01-01	6.204
1978-04-01	6.927
1978-07-01	7.759
1978-10-01	8.433
1979-01-01	8.790
1979-04-01	9.051
1979-07-01	9.758
1979-10-01	9.944
1980-01-01	9.296
1980-04-01	10.575
1980-07-01	10.809
1980-10-01	10.806
1981-01-01	10.570
1981-04-01	10.751
1981-07-01	11.227
1981-10-01	12.406
1982-01-01	12.492
1982-04-01	12.201
1982-07-01	11.972
1982-10-01	12.388
1983-01-01	11.797
1983-04-01	11.514
1983-07-01	11.393
1983-10-01	11.090
1984-01-01	11.141
1984-04-01	10.634
1984-07-01	9.998
1984-10-01	9.773
1985-01-01	9.672
1985-04-01	9.631
1985-07-01	10.132
1985-10-01	9.464
1986-01-01	9.616
1986-04-01	9.496
1986-07-01	9.706
1986-10-01	9.004
1987-01-01	8.920
1987-04-01	8.589
1987-07-01	8.267
1987-10-01	8.533
1988-01-01	8.251
1988-04-01	7.177
1988-07-01	6.252
1988-10-01	6.276
1989-01-01	5.938
1989-04-01	5.602
1989-07-01	6.432
1989-10-01	6.006
1990-01-01	41.151
1990-04-01	41.998
1990-07-01	43.049
1990-10-01	59.445
1991-01-01	60.186
1991-04-01	61.034
1991-07-01	62.670
1991-10-01	66.224
1992-01-01	67.369
1992-04-01	70.014
1992-07-01	71.804
1992-10-01	73.966
1993-01-01	75.340
1993-04-01	97.660
1993-07-01	99.281
1993-10-01	114.941
1994-01-01	121.692
1994-04-01	165.879
1994-07-01	168.904
1994-10-01	172.518
1995-01-01	177.757
1995-04-01	181.188
1995-07-01	185.796
1995-10-01	190.281
1996-01-01	196.697
1996-04-01	203.439
1996-07-01	215.525
1996-10-01	224.695
1997-01-01	237.997
1997-04-01	252.848
1997-07-01	262.458
1997-10-01	261.063
1998-01-01	266.754
1998-04-01	279.492
1998-07-01	286.657
1998-10-01	266.503
1999-01-01	264.167
1999-04-01	274.787
1999-07-01	280.977
1999-10-01	285.848
2000-01-01	296.609
2000-04-01	296.725
2000-07-01	306.668
2000-10-01	305.361
2001-01-01	312.391
2001-04-01	305.504
2001-07-01	310.630
2001-10-01	302.792
2002-01-01	302.416
2002-04-01	305.490
2002-07-01	302.894
2002-10-01	306.032
2003-01-01	300.669
2003-04-01	300.855
2003-07-01	300.753
2003-10-01	309.699
2004-01-01	312.461
2004-04-01	306.179
2004-07-01	306.166
2004-10-01	315.918
2005-01-01	318.319
2005-04-01	285.367
2005-07-01	286.526
2005-10-01	291.043
2006-01-01	294.822
2006-04-01	279.757
2006-07-01	284.961
2006-10-01	293.598
2007-01-01	297.023
2007-04-01	312.360
2007-07-01	315.870
2007-10-01	320.919
2008-01-01	321.038
2008-04-01	321.433
2008-07-01	310.147
2008-10-01	296.385
2009-01-01	295.068
2009-04-01	299.382
2009-07-01	314.291
2009-10-01	339.863
2010-01-01	348.403
2010-04-01	360.991
2010-07-01	383.902
2010-10-01	399.840
2011-01-01	421.054
2011-04-01	439.681
2011-07-01	445.598
2011-10-01	464.099
2012-01-01	480.715
2012-04-01	484.503
2012-07-01	506.726
2012-10-01	523.283
2013-01-01	533.199
2013-04-01	547.797
2013-07-01	567.994
2013-10-01	592.339
2014-01-01	604.274
2014-04-01	631.030
2014-07-01	648.699
2014-10-01	650.097
2015-01-01	653.067
2015-04-01	674.025