Quarter	Millions of US Dollars
1969-01-01	27
1969-04-01	15
1970-07-01	75
1971-01-01	20
1971-07-01	24
1971-10-01	31
1972-04-01	381
1972-07-01	148
1972-10-01	181
1973-01-01	35
1973-04-01	199
1973-07-01	50
1973-10-01	323
1974-01-01	249
1974-04-01	212
1974-07-01	125
1974-10-01	303
1975-01-01	376
1975-04-01	785
1975-07-01	151
1975-10-01	718
1976-01-01	520
1976-04-01	398
1976-07-01	765
1976-10-01	574
1977-01-01	627
1977-04-01	677
1977-07-01	495
1977-10-01	440
1978-01-01	900
1978-04-01	1068
1978-07-01	401
1978-10-01	664
1979-01-01	1196
1979-04-01	99
1979-07-01	300
1979-10-01	60
1980-01-01	120
1980-04-01	21
1980-07-01	-86
1980-10-01	-36
1981-01-01	-18
1981-04-01	1009
1981-07-01	628
1981-10-01	1605
1982-01-01	1543
1982-04-01	979
1982-07-01	1384
1982-10-01	441
1983-01-01	225
1983-04-01	1105
1983-07-01	-179
1983-10-01	1101
1984-01-01	761
1984-04-01	535
1984-07-01	646
1984-10-01	391
1985-01-01	886
1985-04-01	385
1985-07-01	455
1985-10-01	104
1986-01-01	1988
1986-04-01	1590
1986-07-01	933
1986-10-01	1977
1987-01-01	-141
1987-04-01	-271
1987-07-01	-127
1987-10-01	594
1988-01-01	-5
1988-04-01	71
1988-07-01	490
1988-10-01	783
1989-01-01	792
1989-04-01	-792
1989-07-01	-633
1989-10-01	-84
1990-01-01	319
1990-04-01	507
1990-07-01	636
1990-10-01	1467
1991-01-01	1494
1991-04-01	3335
1991-07-01	1823
1991-10-01	1441
1992-01-01	1570
1992-04-01	2219
1992-07-01	1103
1992-10-01	2895
1993-01-01	7893
1993-04-01	2133
1993-07-01	4212
1993-10-01	583
1994-01-01	6946
1994-04-01	2640
1994-07-01	5319
1994-10-01	-620
1995-01-01	1518
1995-04-01	2104
1995-07-01	4557
1995-10-01	-382
1996-01-01	2275
1996-04-01	-1584
1996-07-01	850
1996-10-01	929
1997-01-01	1628
1997-04-01	149
1997-07-01	1532
1997-10-01	-2859
1998-01-01	2764
1998-04-01	-1159
1998-07-01	2260
1998-10-01	4031
1999-01-01	-1697
1999-04-01	11
1999-07-01	-1981
1999-10-01	1650
2000-01-01	-2227
2000-04-01	-3746
2000-07-01	-1280
2000-10-01	-1538
2001-01-01	-60
2001-04-01	-908
2001-07-01	-116
2001-10-01	13
2002-01-01	-206
2002-04-01	-1372
2002-07-01	-762
2002-10-01	2120
2003-01-01	-4538
2003-04-01	2070
2003-07-01	-127
2003-10-01	-2357
2004-01-01	-1249
2004-04-01	-1846
2004-07-01	1232
2004-10-01	-1011
2005-01-01	2034
2005-04-01	1648
2005-07-01	-3419
2005-10-01	1534
2006-01-01	-3253
2006-04-01	-499
2006-07-01	-814
2006-10-01	1587
2007-01-01	929
2007-04-01	-599
2007-07-01	-3648
2007-10-01	-2783
2008-01-01	-1502
2008-04-01	3933
2008-07-01	-2958
2008-10-01	-3806
2009-01-01	-52
2009-04-01	9194
2009-07-01	-772
2009-10-01	8879
2010-01-01	4121
2010-04-01	9160
2010-07-01	2815
2010-10-01	756
2011-01-01	1527
2011-04-01	3469
2011-07-01	4107
2011-10-01	-2338
2012-01-01	660
2012-04-01	6057
2012-07-01	531
2012-10-01	-696
2013-01-01	-961
2013-04-01	-3741
2013-07-01	3131
2013-10-01	-1115
2014-01-01	3088
2014-04-01	91
2014-07-01	-1065
2014-10-01	860
2015-01-01	1435
2015-04-01	-8955
2015-07-01	990
2015-10-01	2174
2016-01-01	985
2016-04-01	30
2016-07-01	-857
2016-10-01	-960
2017-01-01	2019
2017-04-01	6499
2017-07-01	3312
2017-10-01	1939
2018-01-01	585
2018-04-01	-1343