Quarter	Millions of US Dollars
1966-04-01	15
1966-07-01	15
1966-10-01	20
1967-01-01	25
1967-04-01	25
1967-07-01	20
1970-01-01	46
1970-07-01	200
1971-01-01	76
1971-04-01	161
1971-07-01	20
1971-10-01	131
1972-01-01	1164
1972-04-01	273
1972-07-01	546
1972-10-01	539
1973-01-01	596
1973-04-01	669
1973-07-01	304
1973-10-01	385
1974-01-01	364
1974-04-01	484
1974-07-01	353
1974-10-01	1066
1975-01-01	731
1975-04-01	672
1975-07-01	902
1975-10-01	2181
1976-01-01	2205
1976-04-01	1582
1976-07-01	2371
1976-10-01	2044
1977-01-01	1305
1977-04-01	1483
1977-07-01	2214
1977-10-01	1231
1978-01-01	1447
1978-04-01	955
1978-07-01	3383
1978-10-01	1308
1979-01-01	165
1979-04-01	1783
1979-07-01	1808
1979-10-01	1580
1980-01-01	906
1980-04-01	2047
1980-07-01	1005
1980-10-01	1006
1981-01-01	1150
1981-04-01	1682
1981-07-01	1381
1981-10-01	2764
1982-01-01	1153
1982-04-01	1157
1982-07-01	3126
1982-10-01	2387
1983-01-01	2547
1983-04-01	4144
1983-07-01	1723
1983-10-01	3116
1984-01-01	2382
1984-04-01	1869
1984-07-01	2070
1984-10-01	3749
1985-01-01	2801
1985-04-01	2598
1985-07-01	3151
1985-10-01	-68
1986-01-01	5226
1986-04-01	1281
1986-07-01	977
1986-10-01	715
1987-01-01	4573
1987-04-01	911
1987-07-01	1252
1987-10-01	2456
1988-01-01	2741
1988-04-01	1026
1988-07-01	1622
1988-10-01	2604
1989-01-01	4433
1989-04-01	3365
1989-07-01	2674
1989-10-01	2652
1990-01-01	4456
1990-04-01	6538
1990-07-01	2053
1990-10-01	7827
1991-01-01	8993
1991-04-01	4956
1991-07-01	4479
1991-10-01	6693
1992-01-01	10308
1992-04-01	5375
1992-07-01	777
1992-10-01	6837
1993-01-01	9547
1993-04-01	5253
1993-07-01	8258
1993-10-01	5929
1994-01-01	1786
1994-04-01	-923
1994-07-01	1566
1994-10-01	5911
1995-01-01	1807
1995-04-01	3224
1995-07-01	4149
1995-10-01	1254
1996-01-01	3589
1996-04-01	8197
1996-07-01	3116
1996-10-01	8335
1997-01-01	8782
1997-04-01	7657
1997-07-01	2411
1997-10-01	3597
1998-01-01	23444
1998-04-01	9531
1998-07-01	8532
1998-10-01	13564
1999-01-01	14357
1999-04-01	6681
1999-07-01	5350
1999-10-01	-989
2000-01-01	5390
2000-04-01	6997
2000-07-01	3030
2000-10-01	7611
2001-01-01	-1479
2001-04-01	5520
2001-07-01	11114
2001-10-01	1256
2002-01-01	7440
2002-04-01	6752
2002-07-01	9055
2002-10-01	-2989
2003-01-01	9287
2003-04-01	15338
2003-07-01	2561
2003-10-01	-4267
2004-01-01	9999
2004-04-01	7173
2004-07-01	7043
2004-10-01	-1245
2005-01-01	5243
2005-04-01	8565
2005-07-01	19477
2005-10-01	-1441
2006-01-01	6525
2006-04-01	1364
2006-07-01	-4378
2006-10-01	6526
2007-01-01	8317
2007-04-01	13058
2007-07-01	12482
2007-10-01	3565
2008-01-01	25787
2008-04-01	2969
2008-07-01	9288
2008-10-01	19012
2009-01-01	26306
2009-04-01	61491
2009-07-01	20171
2009-10-01	427
2010-01-01	42620
2010-04-01	30153
2010-07-01	17301
2010-10-01	3242
2011-01-01	62722
2011-04-01	38423
2011-07-01	67514
2011-10-01	17244
2012-01-01	185009
2012-04-01	34067
2012-07-01	41261
2012-10-01	24340
2013-01-01	-2186
2013-04-01	59129
2013-07-01	32871
2013-10-01	22620
2014-01-01	69914
2014-04-01	22640
2014-07-01	40692
2014-10-01	4052
2015-01-01	23879
2015-04-01	17851
2015-07-01	22408
2015-10-01	9245
2016-01-01	53634
2016-04-01	35694
2016-07-01	2621
2016-10-01	-7929
2017-01-01	56238
2017-04-01	20564
2017-07-01	21712
2017-10-01	2081
2018-01-01	47048
2018-04-01	-1211