Quarter	Billions of US Dollars
1972-01-01	0.050
1972-04-01	0.086
1972-07-01	0.186
1972-10-01	0.204
1973-01-01	0.221
1973-04-01	0.232
1973-07-01	0.236
1973-10-01	0.225
1974-01-01	0.230
1974-04-01	0.245
1974-07-01	0.341
1974-10-01	0.384
1975-01-01	0.600
1975-04-01	0.955
1975-07-01	0.912
1975-10-01	0.956
1976-01-01	1.061
1976-04-01	1.297
1976-07-01	1.722
1976-10-01	2.010
1977-01-01	2.070
1977-04-01	2.171
1977-07-01	2.680
1977-10-01	3.133
1978-01-01	3.790
1978-04-01	4.045
1978-07-01	4.583
1978-10-01	4.855
1979-01-01	5.032
1979-04-01	5.148
1979-07-01	5.263
1979-10-01	5.376
1980-01-01	5.317
1980-04-01	5.527
1980-07-01	5.608
1980-10-01	5.524
1981-01-01	5.442
1981-04-01	5.306
1981-07-01	5.414
1981-10-01	5.984
1982-01-01	5.803
1982-04-01	5.782
1982-07-01	6.495
1982-10-01	7.074
1983-01-01	7.142
1983-04-01	7.051
1983-07-01	7.464
1983-10-01	8.074
1984-01-01	8.830
1984-04-01	9.080
1984-07-01	9.154
1984-10-01	9.786
1985-01-01	10.557
1985-04-01	11.780
1985-07-01	14.493
1985-10-01	16.178
1986-01-01	18.927
1986-04-01	21.396
1986-07-01	23.277
1986-10-01	25.485
1987-01-01	27.546
1987-04-01	29.137
1987-07-01	30.805
1987-10-01	33.551
1988-01-01	34.094
1988-04-01	35.380
1988-07-01	36.510
1988-10-01	41.339
1989-01-01	43.075
1989-04-01	42.206
1989-07-01	44.858
1989-10-01	44.964
1990-01-01	44.604
1990-04-01	47.444
1990-07-01	50.856
1990-10-01	50.714
1991-01-01	50.312
1991-04-01	49.383
1991-07-01	52.092
1991-10-01	52.406
1992-01-01	51.055
1992-04-01	50.357
1992-07-01	50.121
1992-10-01	47.258
1993-01-01	46.600
1993-04-01	46.536
1993-07-01	45.673
1993-10-01	46.495
1994-01-01	49.765
1994-04-01	53.267
1994-07-01	57.424
1994-10-01	62.253
1995-01-01	65.215
1995-04-01	64.237
1995-07-01	65.782
1995-10-01	67.299
1996-01-01	69.401
1996-04-01	71.756
1996-07-01	74.589
1996-10-01	78.489
1997-01-01	79.461
1997-04-01	82.354
1997-07-01	80.170
1997-10-01	75.031
1998-01-01	75.905
1998-04-01	76.553
1998-07-01	76.174
1998-10-01	76.426
1999-01-01	77.171
1999-04-01	77.878
1999-07-01	83.885
1999-10-01	84.765
2000-01-01	86.848
2000-04-01	93.822
2000-07-01	91.737
2000-10-01	90.382
2001-01-01	88.771
2001-04-01	96.075
2001-07-01	102.383
2001-10-01	103.110
2002-01-01	104.575
2002-04-01	112.390
2002-07-01	115.462
2002-10-01	123.188
2003-01-01	131.693
2003-04-01	144.398
2003-07-01	157.511
2003-10-01	170.118
2004-01-01	187.566
2004-04-01	198.828
2004-07-01	218.075
2004-10-01	234.701
2005-01-01	243.933
2005-04-01	250.173
2005-07-01	249.974
2005-10-01	255.088
2006-01-01	271.739
2006-04-01	289.037
2006-07-01	300.607
2006-10-01	328.473
2007-01-01	344.434
2007-04-01	365.387
2007-07-01	381.126
2007-10-01	385.788
2008-01-01	420.416
2008-04-01	425.356
2008-07-01	397.478
2008-10-01	385.230
2009-01-01	369.034
2009-04-01	401.408
2009-07-01	428.336
2009-10-01	463.547
2010-01-01	470.949
2010-04-01	454.601
2010-07-01	494.663
2010-10-01	502.158
2011-01-01	511.528
2011-04-01	525.897
2011-07-01	511.086
2011-10-01	506.183
2012-01-01	527.205
2012-04-01	518.089
2012-07-01	551.847
2012-10-01	547.187
2013-01-01	548.519
2013-04-01	544.863
2013-07-01	560.192
2013-10-01	576.281
2014-01-01	580.137
2014-04-01	588.662
2014-07-01	566.328
2014-10-01	557.914
2015-01-01	543.635
2015-04-01	561.841