Quarter	Millions of US Dollars
1971-01-01	15
1971-04-01	31
1974-01-01	32
1974-04-01	82
1974-10-01	138
1975-01-01	310
1975-04-01	321
1975-07-01	212
1975-10-01	366
1976-01-01	676
1976-04-01	520
1976-07-01	170
1976-10-01	297
1977-01-01	388
1977-04-01	453
1977-07-01	270
1977-10-01	347
1978-01-01	413
1978-04-01	612
1978-07-01	691
1978-10-01	695
1979-01-01	1202
1979-04-01	1045
1979-07-01	893
1979-10-01	109
1980-01-01	315
1980-04-01	441
1980-07-01	563
1980-10-01	1075
1981-01-01	384
1981-04-01	710
1981-07-01	1366
1981-10-01	746
1982-01-01	1032
1982-04-01	624
1982-07-01	725
1982-10-01	1189
1983-01-01	1967
1983-04-01	1668
1983-07-01	913
1983-10-01	1739
1984-01-01	2890
1984-04-01	1712
1984-07-01	2419
1984-10-01	1608
1985-01-01	3721
1985-04-01	2317
1985-07-01	2981
1985-10-01	2355
1986-01-01	3275
1986-04-01	5142
1986-07-01	5276
1986-10-01	5335
1987-01-01	4981
1987-04-01	8040
1987-07-01	10484
1987-10-01	2463
1988-01-01	3270
1988-04-01	6512
1988-07-01	13754
1988-10-01	4922
1989-01-01	14275
1989-04-01	25021
1989-07-01	12301
1989-10-01	15658
1990-01-01	6387
1990-04-01	-733
1990-07-01	6777
1990-10-01	8300
1991-01-01	6694
1991-04-01	10294
1991-07-01	11566
1991-10-01	8950
1992-01-01	2685
1992-04-01	-668
1992-07-01	-7124
1992-10-01	2843
1993-01-01	-12375
1993-04-01	-17159
1993-07-01	-9314
1993-10-01	-3191
1994-01-01	56
1994-04-01	-6428
1994-07-01	-7515
1994-10-01	-9951
1995-01-01	-6689
1995-04-01	-7162
1995-07-01	-10788
1995-10-01	-3439
1996-01-01	-3910
1996-04-01	-3119
1996-07-01	-4624
1996-10-01	-6387
1997-01-01	-6581
1997-04-01	-6814
1997-07-01	-7412
1997-10-01	-9537
1998-01-01	-11204
1998-04-01	-9324
1998-07-01	-5969
1998-10-01	-2663
1999-01-01	-3261
1999-04-01	-1405
1999-07-01	-1733
1999-10-01	-7148
2000-01-01	-9479
2000-04-01	-3555
2000-07-01	-3167
2000-10-01	-2905
2001-01-01	-3541
2001-04-01	-2673
2001-07-01	-1625
2001-10-01	-2174
2002-01-01	-91
2002-04-01	2681
2002-07-01	-2622
2002-10-01	-2776
2003-01-01	-3109
2003-04-01	399
2003-07-01	-3570
2003-10-01	6315
2004-01-01	2550
2004-04-01	4571
2004-07-01	-738
2004-10-01	1642
2005-01-01	512
2005-04-01	519
2005-07-01	-584
2005-10-01	258
2006-01-01	-87
2006-04-01	223
2006-07-01	-1710
2006-10-01	631
2007-01-01	-3236
2007-04-01	-785
2007-07-01	-424
2007-10-01	425
2008-01-01	-1278
2008-04-01	2358
2008-07-01	585
2008-10-01	-4283
2009-01-01	-2745
2009-04-01	-6736
2009-07-01	-1853
2009-10-01	-859
2010-01-01	-2000
2010-04-01	-2763
2010-07-01	1952
2010-10-01	-2056
2011-01-01	-1401
2011-04-01	-5472
2011-07-01	-3138
2011-10-01	173
2012-01-01	-542
2012-04-01	-766
2012-07-01	4232
2012-10-01	1482
2013-01-01	-713
2013-04-01	3223
2013-07-01	5436
2013-10-01	398
2014-01-01	-1575
2014-04-01	4704
2014-07-01	3501
2014-10-01	2737
2015-01-01	-2557
2015-04-01	1103
2015-07-01	4201
2015-10-01	974
2016-01-01	2972
2016-04-01	5293
2016-07-01	-569
2016-10-01	-486
2017-01-01	5703
2017-04-01	1404
2017-07-01	18731
2017-10-01	3006
2018-01-01	3127
2018-04-01	1506