Quarter	Millions of US Dollars
1971-01-01	86
1971-04-01	51
1971-07-01	24
1971-10-01	51
1972-01-01	121
1972-04-01	78
1972-07-01	117
1972-10-01	191
1973-01-01	35
1973-04-01	300
1973-07-01	54
1973-10-01	401
1974-01-01	109
1974-04-01	424
1974-07-01	65
1974-10-01	72
1975-01-01	103
1975-04-01	326
1975-07-01	138
1975-10-01	111
1976-01-01	100
1976-04-01	211
1976-07-01	110
1976-10-01	239
1977-01-01	218
1977-04-01	195
1977-07-01	172
1977-10-01	243
1978-01-01	387
1978-04-01	478
1978-07-01	375
1978-10-01	484
1979-01-01	232
1979-04-01	262
1979-07-01	117
1979-10-01	-35
1980-01-01	-18
1980-04-01	-43
1980-07-01	149
1980-10-01	-50
1981-01-01	25
1981-04-01	-60
1981-07-01	80
1981-10-01	-48
1982-01-01	-21
1982-04-01	98
1982-07-01	-66
1982-10-01	94
1983-01-01	134
1983-04-01	101
1983-07-01	40
1983-10-01	16
1984-01-01	-17
1984-04-01	234
1984-07-01	149
1984-10-01	340
1985-01-01	107
1985-04-01	753
1985-07-01	-24
1985-10-01	-1131
1986-01-01	-216
1986-04-01	-112
1986-07-01	5
1986-10-01	-259
1987-01-01	-204
1987-04-01	-230
1987-07-01	-365
1987-10-01	-509
1988-01-01	-186
1988-04-01	-251
1988-07-01	-88
1988-10-01	18
1989-01-01	-230
1989-04-01	-396
1989-07-01	141
1989-10-01	-68
1990-01-01	-182
1990-04-01	-764
1990-07-01	-418
1990-10-01	-285
1991-01-01	-311
1991-04-01	835
1991-07-01	-170
1991-10-01	114
1992-01-01	2409
1992-04-01	140
1992-07-01	-255
1992-10-01	-276
1993-01-01	-66
1993-04-01	-516
1993-07-01	56
1993-10-01	708
1994-01-01	722
1994-04-01	-422
1994-07-01	313
1994-10-01	700
1995-01-01	406
1995-04-01	169
1995-07-01	518
1995-10-01	623
1996-01-01	561
1996-04-01	133
1996-07-01	633
1996-10-01	2573
1997-01-01	-76
1997-04-01	1371
1997-07-01	1172
1997-10-01	729
1998-01-01	1815
1998-04-01	705
1998-07-01	525
1998-10-01	126
1999-01-01	1136
1999-04-01	2950
1999-07-01	545
1999-10-01	466
2000-01-01	1963
2000-04-01	1828
2000-07-01	1122
2000-10-01	88
2001-01-01	242
2001-04-01	2297
2001-07-01	2473
2001-10-01	536
2002-01-01	748
2002-04-01	2816
2002-07-01	21
2002-10-01	1150
2003-01-01	1370
2003-04-01	2266
2003-07-01	4572
2003-10-01	159
2004-01-01	5997
2004-04-01	1914
2004-07-01	956
2004-10-01	2134
2005-01-01	1661
2005-04-01	2570
2005-07-01	6828
2005-10-01	5793
2006-01-01	10779
2006-04-01	5755
2006-07-01	4562
2006-10-01	17787
2007-01-01	9372
2007-04-01	9449
2007-07-01	8921
2007-10-01	7467
2008-01-01	-479
2008-04-01	8984
2008-07-01	4095
2008-10-01	-4471
2009-01-01	-2682
2009-04-01	14618
2009-07-01	11951
2009-10-01	9939
2010-01-01	3300
2010-04-01	3604
2010-07-01	9425
2010-10-01	13086
2011-01-01	11615
2011-04-01	-174
2011-07-01	-1936
2011-10-01	17726
2012-01-01	8698
2012-04-01	-697
2012-07-01	8884
2012-10-01	21333
2013-01-01	11891
2013-04-01	5534
2013-07-01	7735
2013-10-01	13277
2014-01-01	2639
2014-04-01	14066
2014-07-01	5145
2014-10-01	3764
2015-01-01	14112
2015-04-01	13766
2015-07-01	1638
2015-10-01	5489
2016-01-01	7616
2016-04-01	34734
2016-07-01	27193
2016-10-01	48228
2017-01-01	16060
2017-04-01	24816
2017-07-01	-2267
2017-10-01	28450
2018-01-01	26788
2018-04-01	39943