Quarter	Millions of US Dollars
1977-04-01	50
1980-04-01	30
1982-04-01	-50
1982-07-01	19
1982-10-01	24
1983-01-01	21
1983-10-01	30
1984-01-01	121
1984-04-01	124
1984-07-01	41
1984-10-01	41
1985-01-01	38
1985-04-01	58
1985-07-01	129
1985-10-01	41
1986-01-01	82
1986-04-01	166
1986-07-01	165
1986-10-01	30
1987-01-01	98
1987-04-01	174
1987-07-01	346
1987-10-01	2
1988-01-01	469
1988-04-01	655
1988-07-01	100
1988-10-01	670
1989-07-01	13
1989-10-01	-100
1990-07-01	-4
1990-10-01	-760
1991-01-01	-741
1991-04-01	66
1991-07-01	-40
1991-10-01	157
1992-04-01	80
1992-07-01	-267
1992-10-01	-36
1993-01-01	512
1993-04-01	-335
1993-07-01	956
1993-10-01	959
1994-01-01	716
1994-04-01	-102
1994-07-01	1501
1994-10-01	430
1995-01-01	848
1995-04-01	1228
1995-07-01	39
1995-10-01	1026
1996-01-01	333
1996-04-01	1601
1996-07-01	-292
1996-10-01	406
1997-01-01	667
1997-04-01	981
1997-07-01	1058
1997-10-01	737
1998-01-01	1017
1998-04-01	385
1998-07-01	-4
1998-10-01	-122
1999-01-01	-438
1999-04-01	3005
1999-07-01	1112
1999-10-01	3514
2000-01-01	1782
2000-04-01	1551
2000-07-01	3025
2000-10-01	1617
2001-01-01	4118
2001-04-01	4475
2001-07-01	2817
2001-10-01	3970
2002-01-01	2314
2002-04-01	4202
2002-07-01	-113
2002-10-01	2189
2003-01-01	3346
2003-04-01	5670
2003-07-01	2576
2003-10-01	6410
2004-01-01	2209
2004-04-01	4003
2004-07-01	319
2004-10-01	3692
2005-01-01	3187
2005-04-01	1649
2005-07-01	-1774
2005-10-01	14985
2006-01-01	5011
2006-04-01	2657
2006-07-01	8529
2006-10-01	11519
2007-01-01	1121
2007-04-01	16102
2007-07-01	1258
2007-10-01	4812
2008-01-01	7003
2008-04-01	10552
2008-07-01	398
2008-10-01	2475
2009-01-01	17344
2009-04-01	14478
2009-07-01	11225
2009-10-01	1397
2010-01-01	10374
2010-04-01	-12260
2010-07-01	-1930
2010-10-01	-3513
2011-01-01	-2455
2011-04-01	-12223
2011-07-01	-4100
2011-10-01	1362
2012-01-01	-11649
2012-04-01	-7233
2012-07-01	-11082
2012-10-01	4270
2013-01-01	-2955
2013-04-01	-6166
2013-07-01	-1829
2013-10-01	-1603
2014-01-01	-4236
2014-04-01	-12934
2014-07-01	1223
2014-10-01	-8719
2015-01-01	-4533
2015-04-01	-818
2015-07-01	-2256
2015-10-01	-2757
2016-01-01	-678
2016-04-01	-2225
2016-07-01	681
2016-10-01	-7889
2017-01-01	-3732
2017-04-01	1405
2017-07-01	-2561
2017-10-01	-4689
2018-01-01	973
2018-04-01	747