Quarter	Millions of US Dollars
1980-07-01	25
1982-01-01	43
1982-04-01	20
1983-04-01	40
1983-07-01	20
1984-10-01	83
1985-01-01	116
1985-04-01	129
1985-07-01	294
1985-10-01	206
1986-01-01	353
1986-04-01	389
1986-07-01	329
1986-10-01	156
1987-01-01	192
1987-04-01	200
1987-07-01	216
1987-10-01	364
1988-01-01	230
1988-04-01	158
1988-07-01	239
1988-10-01	194
1989-04-01	154
1989-10-01	100
1990-07-01	-39
1991-07-01	143
1991-10-01	22
1992-01-01	-155
1992-04-01	48
1992-07-01	219
1992-10-01	156
1993-01-01	-290
1993-04-01	336
1993-07-01	1341
1993-10-01	678
1994-01-01	1472
1994-04-01	422
1994-07-01	1219
1994-10-01	668
1995-01-01	-142
1995-04-01	-237
1995-07-01	784
1995-10-01	-198
1996-01-01	-205
1996-04-01	-238
1996-07-01	1550
1996-10-01	725
1997-01-01	709
1997-04-01	2585
1997-07-01	398
1997-10-01	198
1998-01-01	379
1998-04-01	-451
1998-07-01	-931
1998-10-01	536
1999-01-01	-456
1999-04-01	263
1999-07-01	-211
1999-10-01	368
2000-01-01	-329
2000-04-01	49
2000-07-01	-306
2000-10-01	951
2001-01-01	-218
2001-04-01	1963
2001-07-01	-1317
2001-10-01	152
2002-01-01	1519
2002-04-01	-268
2002-07-01	-574
2002-10-01	-943
2003-01-01	-868
2003-04-01	336
2003-07-01	468
2003-10-01	2696
2004-01-01	-967
2004-04-01	-239
2004-07-01	1426
2004-10-01	3380
2005-01-01	518
2005-04-01	-79
2005-07-01	1262
2005-10-01	1302
2006-01-01	-35
2006-04-01	758
2006-07-01	-149
2006-10-01	889
2007-01-01	2289
2007-04-01	5439
2007-07-01	2707
2007-10-01	624
2008-01-01	525
2008-04-01	2705
2008-07-01	2447
2008-10-01	-539
2009-01-01	-1124
2009-04-01	582
2009-07-01	84
2009-10-01	1480
2010-01-01	2994
2010-04-01	3295
2010-07-01	7974
2010-10-01	10501
2011-01-01	11597
2011-04-01	20537
2011-07-01	5901
2011-10-01	7291
2012-01-01	11951
2012-04-01	19896
2012-07-01	5150
2012-10-01	18608
2013-01-01	21236
2013-04-01	29319
2013-07-01	14196
2013-10-01	34536
2014-01-01	33353
2014-04-01	52114
2014-07-01	29411
2014-10-01	47161
2015-01-01	20511
2015-04-01	35562
2015-07-01	9248
2015-10-01	35951
2016-01-01	-3082
2016-04-01	41006
2016-07-01	40432
2016-10-01	39122
2017-01-01	55536
2017-04-01	52537
2017-07-01	53171
2017-10-01	74574
2018-01-01	50541
2018-04-01	25295