Quarter	Millions of US Dollars
1968-04-01	15
1971-01-01	40
1971-04-01	40
1971-07-01	2
1971-10-01	2
1972-01-01	96
1972-04-01	102
1972-07-01	50
1972-10-01	45
1973-01-01	97
1973-04-01	87
1973-10-01	13
1974-01-01	144
1974-04-01	27
1974-07-01	256
1974-10-01	164
1975-01-01	643
1975-04-01	523
1975-07-01	311
1975-10-01	526
1976-01-01	862
1976-04-01	904
1976-07-01	569
1976-10-01	654
1977-01-01	495
1977-04-01	301
1977-07-01	227
1977-10-01	796
1978-01-01	417
1978-04-01	513
1978-07-01	382
1978-10-01	68
1979-01-01	494
1979-04-01	619
1979-07-01	485
1979-10-01	489
1980-01-01	53
1980-04-01	568
1980-07-01	410
1980-10-01	958
1981-01-01	874
1981-04-01	378
1981-07-01	259
1981-10-01	553
1982-01-01	1915
1982-04-01	1784
1982-07-01	1811
1982-10-01	1556
1983-01-01	1929
1983-04-01	1749
1983-07-01	556
1983-10-01	1563
1984-01-01	2024
1984-04-01	858
1984-07-01	2597
1984-10-01	1409
1985-01-01	1899
1985-04-01	606
1985-07-01	1909
1985-10-01	-448
1986-01-01	225
1986-04-01	2349
1986-07-01	1463
1986-10-01	1396
1987-01-01	1216
1987-04-01	1693
1987-07-01	42
1987-10-01	-85
1988-01-01	2525
1988-04-01	4123
1988-07-01	2731
1988-10-01	2291
1989-01-01	3494
1989-04-01	2143
1989-07-01	1871
1989-10-01	1034
1990-01-01	2615
1990-04-01	1767
1990-07-01	3324
1990-10-01	1834
1991-01-01	1910
1991-04-01	3641
1991-07-01	2494
1991-10-01	4527
1992-01-01	3833
1992-04-01	1682
1992-07-01	1101
1992-10-01	6341
1993-01-01	2749
1993-04-01	-101
1993-07-01	13886
1993-10-01	3736
1994-01-01	3370
1994-04-01	-67
1994-07-01	2510
1994-10-01	2616
1995-01-01	-428
1995-04-01	236
1995-07-01	1255
1995-10-01	2948
1996-01-01	764
1996-04-01	9262
1996-07-01	3134
1996-10-01	465
1997-01-01	6488
1997-04-01	-734
1997-07-01	4639
1997-10-01	1219
1998-01-01	10814
1998-04-01	4494
1998-07-01	9687
1998-10-01	5317
1999-01-01	13192
1999-04-01	13295
1999-07-01	13529
1999-10-01	13586
2000-01-01	13976
2000-04-01	12387
2000-07-01	20118
2000-10-01	15074
2001-01-01	34247
2001-04-01	15316
2001-07-01	17839
2001-10-01	24492
2002-01-01	4305
2002-04-01	20993
2002-07-01	7439
2002-10-01	20772
2003-01-01	21674
2003-04-01	40797
2003-07-01	22314
2003-10-01	30630
2004-01-01	18300
2004-04-01	33223
2004-07-01	24267
2004-10-01	43294
2005-01-01	39033
2005-04-01	46193
2005-07-01	6023
2005-10-01	41426
2006-01-01	38729
2006-04-01	33214
2006-07-01	32527
2006-10-01	82454
2007-01-01	31210
2007-04-01	85827
2007-07-01	3432
2007-10-01	43414
2008-01-01	18869
2008-04-01	100053
2008-07-01	16360
2008-10-01	-7145
2009-01-01	14806
2009-04-01	98472
2009-07-01	20915
2009-10-01	31831
2010-01-01	57137
2010-04-01	-7975
2010-07-01	32205
2010-10-01	17872
2011-01-01	95583
2011-04-01	14598
2011-07-01	-21797
2011-10-01	7528
2012-01-01	34859
2012-04-01	-22459
2012-07-01	9037
2012-10-01	-6625
2013-01-01	5667
2013-04-01	4135
2013-07-01	-6428
2013-10-01	-15760
2014-01-01	30141
2014-04-01	8852
2014-07-01	7340
2014-10-01	-26170
2015-01-01	1681
2015-04-01	-29471
2015-07-01	-22578
2015-10-01	-7960
2016-01-01	-3045
2016-04-01	21431
2016-07-01	13816
2016-10-01	18376
2017-01-01	9507
2017-04-01	-3674
2017-07-01	-1633
2017-10-01	14757
2018-01-01	-7576
2018-04-01	15871