Quarter	Billions of US Dollars
1966-01-01	0.015
1968-01-01	0.110
1968-04-01	0.060
1968-07-01	0.020
1969-10-01	0.008
1972-07-01	0.027
1975-10-01	0.015
1977-01-01	0.025
1977-10-01	0.090
1978-07-01	0.278
1978-10-01	0.026
1979-01-01	0.081
1983-01-01	0.029
1983-04-01	0.079
1983-07-01	0.100
1983-10-01	0.200
1984-04-01	0.050
1984-07-01	0.025
1984-10-01	0.166
1985-01-01	0.400
1985-04-01	0.234
1985-07-01	0.316
1985-10-01	0.569
1986-01-01	0.395
1986-04-01	0.827
1986-07-01	0.462
1986-10-01	0.426
1987-01-01	0.485
1987-04-01	0.758
1987-07-01	0.881
1987-10-01	1.171
1988-01-01	0.631
1988-04-01	1.601
1988-07-01	0.380
1988-10-01	0.875
1989-01-01	1.382
1989-04-01	0.834
1989-07-01	1.804
1989-10-01	0.611
1990-01-01	1.343
1990-04-01	1.002
1990-07-01	1.864
1990-10-01	1.011
1991-01-01	3.070
1991-04-01	1.649
1991-07-01	0.611
1991-10-01	1.286
1992-01-01	2.496
1992-04-01	1.575
1992-07-01	1.976
1992-10-01	1.218
1993-01-01	1.674
1993-04-01	2.186
1993-07-01	3.223
1993-10-01	5.431
1994-01-01	3.831
1994-04-01	4.792
1994-07-01	3.130
1994-10-01	4.991
1995-01-01	4.873
1995-04-01	7.421
1995-07-01	7.551
1995-10-01	5.294
1996-01-01	12.920
1996-04-01	11.753
1996-07-01	9.611
1996-10-01	19.491
1997-01-01	16.342
1997-04-01	13.661
1997-07-01	24.725
1997-10-01	22.790
1998-01-01	18.869
1998-04-01	20.738
1998-07-01	17.064
1998-10-01	11.576
1999-01-01	22.431
1999-04-01	20.332
1999-07-01	14.453
1999-10-01	18.184
2000-01-01	29.034
2000-04-01	19.899
2000-07-01	36.074
2000-10-01	23.366
2001-01-01	40.077
2001-04-01	36.272
2001-07-01	25.475
2001-10-01	25.680
2002-01-01	25.862
2002-04-01	24.696
2002-07-01	20.247
2002-10-01	17.696
2003-01-01	21.595
2003-04-01	20.109
2003-07-01	21.194
2003-10-01	20.503
2004-01-01	24.475
2004-04-01	20.990
2004-07-01	24.731
2004-10-01	27.563
2005-01-01	24.471
2005-04-01	31.991
2005-07-01	43.945
2005-10-01	72.279
2006-01-01	77.678
2006-04-01	79.890
2006-07-01	110.197
2006-10-01	142.340
2007-01-01	129.148
2007-04-01	147.296
2007-07-01	65.702
2007-10-01	38.038
2008-01-01	30.837
2008-04-01	29.507
2008-07-01	23.686
2008-10-01	13.897
2009-01-01	16.630
2009-04-01	27.440
2009-07-01	22.008
2009-10-01	21.869
2010-01-01	19.496
2010-04-01	16.415
2010-07-01	24.348
2010-10-01	24.174
2011-01-01	29.452
2011-04-01	18.442
2011-07-01	14.960
2011-10-01	23.261
2012-01-01	42.678
2012-04-01	26.491
2012-07-01	25.386
2012-10-01	47.062
2013-01-01	33.903
2013-04-01	41.089
2013-07-01	29.808
2013-10-01	37.468
2014-01-01	33.353
2014-04-01	59.005
2014-07-01	32.079
2014-10-01	38.480
2015-01-01	36.283
2015-04-01	32.294