Quarter	Millions of US Dollars
1972-01-01	40
1972-04-01	40
1972-07-01	31
1972-10-01	105
1973-01-01	65
1973-07-01	38
1973-10-01	66
1974-10-01	25
1975-01-01	75
1975-04-01	59
1976-01-01	50
1976-04-01	122
1976-07-01	40
1976-10-01	109
1977-01-01	115
1977-04-01	389
1977-07-01	143
1977-10-01	436
1978-01-01	712
1978-04-01	324
1978-07-01	150
1978-10-01	433
1979-01-01	352
1979-04-01	149
1979-07-01	129
1979-10-01	207
1980-01-01	-75
1980-04-01	211
1980-07-01	196
1980-10-01	99
1981-01-01	45
1981-04-01	150
1981-07-01	90
1981-10-01	189
1982-01-01	168
1982-04-01	-341
1982-07-01	175
1982-10-01	-25
1983-01-01	-383
1983-04-01	-67
1983-07-01	50
1983-10-01	-75
1984-01-01	-100
1984-04-01	-66
1984-07-01	-134
1984-10-01	-47
1985-01-01	-99
1985-04-01	-6
1985-07-01	-21
1985-10-01	-515
1986-01-01	-55
1986-04-01	-206
1986-07-01	-9
1986-10-01	-268
1987-01-01	-262
1987-04-01	-24
1987-07-01	-115
1987-10-01	-247
1988-01-01	91
1988-04-01	-315
1988-07-01	-254
1988-10-01	205
1989-01-01	11
1989-04-01	-23
1989-07-01	933
1989-10-01	-429
1990-01-01	34390
1990-04-01	-331
1990-07-01	-206
1990-10-01	15573
1991-01-01	386
1991-04-01	164
1991-07-01	241
1991-10-01	731
1992-01-01	-58
1992-04-01	50
1992-07-01	250
1992-10-01	170
1993-01-01	48
1993-04-01	17879
1993-07-01	509
1993-10-01	10397
1994-01-01	782
1994-04-01	42611
1994-07-01	1589
1994-10-01	1162
1995-01-01	5078
1995-04-01	3142
1995-07-01	4454
1995-10-01	3495
1996-01-01	6029
1996-04-01	3846
1996-07-01	8795
1996-10-01	5338
1997-01-01	12952
1997-04-01	7506
1997-07-01	3216
1997-10-01	1102
1998-01-01	4640
1998-04-01	6319
1998-07-01	2660
1998-10-01	-20750
1999-01-01	3061
1999-04-01	9481
1999-07-01	3471
1999-10-01	8121
2000-01-01	11407
2000-04-01	-550
2000-07-01	15940
2000-10-01	-763
2001-01-01	9637
2001-04-01	-4208
2001-07-01	114
2001-10-01	-4202
2002-01-01	4513
2002-04-01	-2623
2002-07-01	184
2002-10-01	753
2003-01-01	-5374
2003-04-01	-1784
2003-07-01	-1382
2003-10-01	2351
2004-01-01	4767
2004-04-01	-1789
2004-07-01	1720
2004-10-01	5127
2005-01-01	5009
2005-04-01	-27833
2005-07-01	565
2005-10-01	3252
2006-01-01	-73
2006-04-01	-16733
2006-07-01	2656
2006-10-01	2311
2007-01-01	-934
2007-04-01	1952
2007-07-01	-1434
2007-10-01	-510
2008-01-01	-6524
2008-04-01	2107
2008-07-01	-1626
2008-10-01	-5735
2009-01-01	1463
2009-04-01	-5098
2009-07-01	3583
2009-10-01	9059
2010-01-01	-4731
2010-04-01	4341
2010-07-01	5546
2010-10-01	4966
2011-01-01	-1131
2011-04-01	-1029
2011-07-01	6012
2011-10-01	6136
2012-01-01	2352
2012-04-01	3048
2012-07-01	1406
2012-10-01	3869
2013-01-01	107
2013-04-01	2921
2013-07-01	3957
2013-10-01	10200
2014-01-01	3913
2014-04-01	8757
2014-07-01	4902
2014-10-01	1998
2015-01-01	10850
2015-04-01	3104
2015-07-01	-866
2015-10-01	204
2016-01-01	11728
2016-04-01	20270
2016-07-01	8602
2016-10-01	8143
2017-01-01	18318
2017-04-01	16814
2017-07-01	5116
2017-10-01	5837
2018-01-01	19375
2018-04-01	433