Quarter	Millions of US Dollars
1971-10-01	31
1972-01-01	82
1972-04-01	40
1972-07-01	51
1972-10-01	145
1973-01-01	95
1973-04-01	25
1973-07-01	76
1973-10-01	109
1974-01-01	5
1974-07-01	2
1974-10-01	75
1975-01-01	168
1975-04-01	147
1975-07-01	49
1975-10-01	62
1976-01-01	62
1976-04-01	193
1976-07-01	131
1976-10-01	272
1977-01-01	319
1977-04-01	612
1977-07-01	877
1977-10-01	938
1978-01-01	1176
1978-04-01	685
1978-07-01	396
1978-10-01	610
1979-01-01	574
1979-04-01	264
1979-07-01	483
1979-10-01	289
1980-01-01	-47
1980-04-01	591
1980-07-01	313
1980-10-01	262
1981-01-01	170
1981-04-01	781
1981-07-01	434
1981-10-01	870
1982-01-01	613
1982-04-01	-78
1982-07-01	-9
1982-10-01	-93
1983-01-01	-432
1983-04-01	-153
1983-07-01	-42
1983-10-01	-235
1984-01-01	-144
1984-04-01	-153
1984-07-01	-339
1984-10-01	-72
1985-01-01	-124
1985-04-01	-109
1985-07-01	-148
1985-10-01	-1011
1986-01-01	-251
1986-04-01	-476
1986-07-01	-157
1986-10-01	-669
1987-01-01	-512
1987-04-01	-274
1987-07-01	-328
1987-10-01	-556
1988-01-01	-141
1988-04-01	-758
1988-07-01	-828
1988-10-01	-235
1989-01-01	-139
1989-04-01	-122
1989-07-01	728
1989-10-01	-417
1990-01-01	35250
1990-04-01	697
1990-07-01	552
1990-10-01	16172
1991-01-01	1522
1991-04-01	1042
1991-07-01	1114
1991-10-01	2711
1992-01-01	1371
1992-04-01	2096
1992-07-01	1284
1992-10-01	2551
1993-01-01	1011
1993-04-01	22202
1993-07-01	7890
1993-10-01	16339
1994-01-01	7450
1994-04-01	42797
1994-07-01	2866
1994-10-01	2706
1995-01-01	-239
1995-04-01	2547
1995-07-01	6733
1995-10-01	5107
1996-01-01	7981
1996-04-01	9010
1996-07-01	10604
1996-10-01	9960
1997-01-01	15387
1997-04-01	14237
1997-07-01	12246
1997-10-01	-767
1998-01-01	9601
1998-04-01	12899
1998-07-01	1068
1998-10-01	-22558
1999-01-01	-609
1999-04-01	12966
1999-07-01	3815
1999-10-01	7843
2000-01-01	13660
2000-04-01	233
2000-07-01	14028
2000-10-01	-4509
2001-01-01	10803
2001-04-01	-5116
2001-07-01	-180
2001-10-01	-3999
2002-01-01	1476
2002-04-01	-5352
2002-07-01	-2375
2002-10-01	-195
2003-01-01	-5712
2003-04-01	-2292
2003-07-01	-1194
2003-10-01	2406
2004-01-01	3622
2004-04-01	-6353
2004-07-01	-1060
2004-10-01	3517
2005-01-01	5860
2005-04-01	-28717
2005-07-01	1349
2005-10-01	5812
2006-01-01	2555
2006-04-01	-17208
2006-07-01	5256
2006-10-01	6410
2007-01-01	1311
2007-04-01	14573
2007-07-01	-268
2007-10-01	3373
2008-01-01	-4955
2008-04-01	469
2008-07-01	-3788
2008-10-01	-10995
2009-01-01	1123
2009-04-01	-624
2009-07-01	12416
2009-10-01	25900
2010-01-01	11354
2010-04-01	16099
2010-07-01	17566
2010-10-01	16756
2011-01-01	18087
2011-04-01	16315
2011-07-01	10768
2011-10-01	18428
2012-01-01	14494
2012-04-01	8729
2012-07-01	19729
2012-10-01	16859
2013-01-01	11806
2013-04-01	15503
2013-07-01	17728
2013-10-01	24472
2014-01-01	9567
2014-04-01	26167
2014-07-01	22878
2014-10-01	7509
2015-01-01	12103
2015-04-01	17909
2015-07-01	2136
2015-10-01	-69
2016-01-01	22644
2016-04-01	22504
2016-07-01	12872
2016-10-01	19240
2017-01-01	20853
2017-04-01	19346
2017-07-01	24334
2017-10-01	11818
2018-01-01	26273
2018-04-01	2193