Quarter	Millions of US Dollars
1972-01-01	42
1972-07-01	20
1973-07-01	13
1973-10-01	36
1974-10-01	50
1975-01-01	58
1975-04-01	24
1975-10-01	25
1976-10-01	56
1977-04-01	117
1977-07-01	283
1977-10-01	267
1978-01-01	145
1978-04-01	34
1978-07-01	50
1978-10-01	100
1979-01-01	65
1979-07-01	73
1980-01-01	56
1980-04-01	125
1980-10-01	60
1981-04-01	357
1981-07-01	395
1981-10-01	446
1982-01-01	170
1982-04-01	109
1982-07-01	-19
1982-10-01	-40
1983-01-01	-30
1983-04-01	-27
1983-07-01	-47
1983-10-01	-137
1984-04-01	-37
1984-07-01	-101
1985-04-01	-23
1985-07-01	-35
1985-10-01	-109
1986-10-01	-211
1987-01-01	-129
1987-04-01	-109
1987-07-01	-2
1987-10-01	-185
1988-01-01	-29
1988-04-01	-253
1988-07-01	-388
1988-10-01	-291
1989-04-01	-117
1989-07-01	-85
1989-10-01	46
1990-01-01	1046
1990-04-01	548
1990-07-01	293
1990-10-01	398
1991-01-01	168
1991-04-01	925
1991-07-01	139
1991-10-01	100
1992-01-01	96
1992-04-01	167
1992-07-01	324
1992-10-01	1537
1993-01-01	518
1993-04-01	1761
1993-07-01	868
1993-10-01	912
1994-01-01	2817
1994-04-01	-35
1994-07-01	171
1994-10-01	-375
1995-01-01	-1620
1995-04-01	23
1995-07-01	253
1995-10-01	16
1996-01-01	-297
1996-04-01	-56
1996-07-01	-377
1996-10-01	256
1997-01-01	545
1997-04-01	2215
1997-07-01	2249
1997-10-01	-686
1998-01-01	1080
1998-04-01	-94
1998-07-01	914
1998-10-01	33
1999-01-01	-501
1999-04-01	1821
1999-07-01	100
1999-10-01	11
2000-01-01	1187
2000-04-01	98
2000-07-01	14
2000-10-01	-1015
2001-01-01	845
2001-04-01	-63
2001-07-01	446
2001-10-01	-334
2002-01-01	-1346
2002-04-01	-1025
2002-07-01	-1042
2002-10-01	90
2003-01-01	-920
2003-04-01	-984
2003-07-01	-895
2003-10-01	818
2004-01-01	301
2004-04-01	-1868
2004-07-01	-61
2004-10-01	-271
2005-01-01	1833
2005-04-01	774
2005-07-01	120
2005-10-01	811
2006-01-01	455
2006-04-01	-168
2006-07-01	-34
2006-10-01	1384
2007-01-01	1113
2007-04-01	-100
2007-07-01	-670
2007-10-01	1644
2008-01-01	-356
2008-04-01	-893
2008-07-01	5
2008-10-01	-2221
2009-01-01	682
2009-04-01	373
2009-07-01	2340
2009-10-01	5354
2010-01-01	6523
2010-04-01	5161
2010-07-01	2137
2010-10-01	-2880
2011-01-01	3132
2011-04-01	4439
2011-07-01	4662
2011-10-01	4736
2012-01-01	4445
2012-04-01	1866
2012-07-01	7751
2012-10-01	3952
2013-01-01	4211
2013-04-01	5009
2013-07-01	9653
2013-10-01	11596
2014-01-01	3294
2014-04-01	5792
2014-07-01	4026
2014-10-01	4237
2015-01-01	2593
2015-04-01	7322
2015-07-01	263
2015-10-01	1179
2016-01-01	16738
2016-04-01	1172
2016-07-01	1149
2016-10-01	4349
2017-01-01	2697
2017-04-01	-1300
2017-07-01	7369
2017-10-01	343
2018-01-01	2731
2018-04-01	3868