Quarter	Millions of US Dollars
1967-04-01	20
1971-01-01	31
1971-10-01	46
1972-01-01	31
1972-07-01	31
1972-10-01	66
1973-01-01	31
1973-04-01	17
1974-07-01	25
1975-01-01	21
1975-04-01	18
1975-07-01	25
1976-01-01	10
1976-04-01	67
1976-07-01	28
1976-10-01	142
1977-01-01	204
1977-04-01	190
1977-07-01	22
1977-10-01	86
1978-04-01	227
1978-07-01	22
1979-01-01	209
1979-04-01	136
1979-07-01	58
1979-10-01	38
1980-01-01	101
1980-04-01	118
1980-07-01	56
1980-10-01	69
1981-01-01	-13
1981-04-01	129
1981-10-01	64
1982-01-01	195
1982-04-01	259
1982-10-01	22
1983-01-01	229
1983-04-01	123
1983-07-01	146
1983-10-01	341
1984-01-01	493
1984-04-01	-224
1984-07-01	55
1984-10-01	668
1985-01-01	476
1985-04-01	366
1985-07-01	49
1985-10-01	-170
1986-01-01	-283
1986-04-01	-37
1986-07-01	-44
1986-10-01	-388
1987-01-01	-313
1987-04-01	-510
1987-07-01	284
1987-10-01	-62
1988-01-01	161
1988-04-01	-256
1988-07-01	33
1988-10-01	290
1989-01-01	-29
1989-04-01	-59
1989-07-01	-264
1989-10-01	-145
1990-01-01	-135
1990-04-01	389
1990-07-01	344
1990-10-01	917
1991-01-01	-141
1991-04-01	299
1991-07-01	-4
1991-10-01	925
1992-01-01	969
1992-04-01	1129
1992-07-01	1694
1992-10-01	57
1993-01-01	2340
1993-04-01	1171
1993-07-01	1203
1993-10-01	12
1994-01-01	-698
1994-04-01	-180
1994-07-01	1520
1994-10-01	-214
1995-01-01	4328
1995-04-01	-240
1995-07-01	-44
1995-10-01	-435
1996-01-01	-359
1996-04-01	33
1996-07-01	2362
1996-10-01	1005
1997-01-01	1702
1997-04-01	965
1997-07-01	1555
1997-10-01	555
1998-01-01	964
1998-04-01	1827
1998-07-01	1815
1998-10-01	903
1999-01-01	861
1999-04-01	3830
1999-07-01	1990
1999-10-01	4035
2000-01-01	-1473
2000-04-01	2256
2000-07-01	2630
2000-10-01	438
2001-01-01	723
2001-04-01	4635
2001-07-01	1407
2001-10-01	4117
2002-01-01	5860
2002-04-01	3711
2002-07-01	2928
2002-10-01	7999
2003-01-01	10336
2003-04-01	16304
2003-07-01	7677
2003-10-01	16301
2004-01-01	12641
2004-04-01	11461
2004-07-01	1273
2004-10-01	17879
2005-01-01	18139
2005-04-01	35673
2005-07-01	8225
2005-10-01	49825
2006-01-01	61947
2006-04-01	48529
2006-07-01	23739
2006-10-01	29153
2007-01-01	54017
2007-04-01	42117
2007-07-01	22806
2007-10-01	5113
2008-01-01	4797
2008-04-01	58088
2008-07-01	28968
2008-10-01	9209
2009-01-01	33476
2009-04-01	17741
2009-07-01	24416
2009-10-01	22557
2010-01-01	4640
2010-04-01	-16844
2010-07-01	30353
2010-10-01	-1879
2011-01-01	9918
2011-04-01	-8039
2011-07-01	1422
2011-10-01	-1274
2012-01-01	37723
2012-04-01	-39333
2012-07-01	-22843
2012-10-01	14024
2013-01-01	-7266
2013-04-01	-10785
2013-07-01	-24872
2013-10-01	1227
2014-01-01	-25584
2014-04-01	2900
2014-07-01	-15912
2014-10-01	-15849
2015-01-01	-5391
2015-04-01	-12952
2015-07-01	-7320
2015-10-01	-4152
2016-01-01	-26425
2016-04-01	-4460
2016-07-01	-4807
2016-10-01	-14478
2017-01-01	-17038
2017-04-01	7634
2017-07-01	-6068
2017-10-01	259
2018-01-01	3466
2018-04-01	-9223