Quarter	Millions of US Dollars
1966-01-01	15
1968-01-01	110
1968-04-01	60
1968-07-01	20
1969-10-01	8
1972-07-01	27
1975-10-01	15
1977-01-01	25
1977-10-01	90
1978-07-01	278
1978-10-01	26
1979-01-01	81
1980-10-01	-15
1983-01-01	29
1983-04-01	79
1983-07-01	100
1983-10-01	200
1984-01-01	-25
1984-04-01	50
1984-07-01	25
1984-10-01	148
1985-01-01	153
1985-04-01	313
1985-07-01	467
1985-10-01	260
1986-01-01	518
1986-04-01	704
1986-07-01	587
1986-10-01	92
1987-01-01	259
1987-04-01	506
1987-07-01	953
1987-10-01	1184
1988-01-01	233
1988-04-01	1050
1988-07-01	760
1988-10-01	610
1989-01-01	1463
1989-04-01	783
1989-07-01	1025
1989-10-01	858
1990-01-01	702
1990-04-01	233
1990-07-01	1790
1990-10-01	598
1991-01-01	1641
1991-04-01	962
1991-07-01	383
1991-10-01	641
1992-01-01	951
1992-04-01	937
1992-07-01	1758
1992-10-01	443
1993-01-01	167
1993-04-01	-340
1993-07-01	6155
1993-10-01	4861
1994-01-01	3487
1994-04-01	5257
1994-07-01	2915
1994-10-01	3959
1995-01-01	2527
1995-04-01	6830
1995-07-01	6436
1995-10-01	4368
1996-01-01	9156
1996-04-01	11375
1996-07-01	4279
1996-10-01	18150
1997-01-01	10069
1997-04-01	7508
1997-07-01	22307
1997-10-01	20034
1998-01-01	13281
1998-04-01	18384
1998-07-01	12056
1998-10-01	3649
1999-01-01	12563
1999-04-01	18634
1999-07-01	11008
1999-10-01	13744
2000-01-01	22599
2000-04-01	10243
2000-07-01	21775
2000-10-01	16601
2001-01-01	27367
2001-04-01	17141
2001-07-01	12956
2001-10-01	13595
2002-01-01	6471
2002-04-01	14987
2002-07-01	3148
2002-10-01	-479
2003-01-01	1408
2003-04-01	-3142
2003-07-01	-1562
2003-10-01	-2287
2004-01-01	1429
2004-04-01	-1863
2004-07-01	4328
2004-10-01	3605
2005-01-01	6493
2005-04-01	2439
2005-07-01	14108
2005-10-01	39171
2006-01-01	54654
2006-04-01	49945
2006-07-01	75177
2006-10-01	125897
2007-01-01	104050
2007-04-01	106038
2007-07-01	46556
2007-10-01	20887
2008-01-01	-10111
2008-04-01	-3543
2008-07-01	-10185
2008-10-01	-12306
2009-01-01	-13255
2009-04-01	7641
2009-07-01	4993
2009-10-01	-5309
2010-01-01	1783
2010-04-01	-8113
2010-07-01	6619
2010-10-01	7814
2011-01-01	-5622
2011-04-01	-9726
2011-07-01	-5534
2011-10-01	6329
2012-01-01	19821
2012-04-01	5700
2012-07-01	13235
2012-10-01	30818
2013-01-01	13508
2013-04-01	21460
2013-07-01	3068
2013-10-01	18118
2014-01-01	12523
2014-04-01	34762
2014-07-01	18277
2014-10-01	11814
2015-01-01	14551
2015-04-01	20443
2015-07-01	7867
2015-10-01	-3190
2016-01-01	1778
2016-04-01	19014
2016-07-01	-3701
2016-10-01	8874
2017-01-01	10958
2017-04-01	47112
2017-07-01	30444
2017-10-01	51074
2018-01-01	48382
2018-04-01	62237