Quarter	Millions of US Dollars
1984-07-01	50
1986-04-01	100
1987-01-01	-50
1988-01-01	75
1988-07-01	268
1989-01-01	456
1989-07-01	441
1990-01-01	291
1993-04-01	-100
1994-01-01	-94
1994-07-01	-50
1995-01-01	-338
1995-07-01	-448
1995-10-01	33
1996-01-01	70
1996-04-01	46
1996-07-01	-993
1996-10-01	1107
1997-01-01	1353
1997-04-01	3135
1997-07-01	1176
1997-10-01	1562
1998-01-01	781
1998-04-01	4854
1998-07-01	6336
1998-10-01	-224
1999-01-01	-81
1999-04-01	-194
1999-07-01	-211
1999-10-01	-269
2000-01-01	-100
2000-04-01	-281
2000-07-01	19844
2001-01-01	-150
2001-04-01	-359
2001-10-01	253
2002-01-01	661
2002-04-01	320
2002-10-01	1855
2003-01-01	2504
2003-04-01	-215
2003-07-01	1549
2003-10-01	2325
2004-01-01	533
2004-04-01	2173
2004-07-01	3165
2004-10-01	2236
2005-01-01	2030
2005-04-01	5326
2005-07-01	892
2005-10-01	4942
2006-01-01	2747
2006-04-01	2517
2006-07-01	4455
2006-10-01	14712
2007-01-01	9527
2007-04-01	13540
2007-07-01	1315
2007-10-01	11024
2008-01-01	192
2008-04-01	10438
2008-07-01	2191
2008-10-01	-2950
2009-01-01	-3648
2009-04-01	2595
2009-07-01	755
2009-10-01	-3109
2010-01-01	1110
2010-04-01	5080
2010-07-01	7848
2010-10-01	13746
2011-01-01	4755
2011-04-01	6377
2011-07-01	-2608
2011-10-01	-140
2012-01-01	4564
2012-04-01	19803
2012-07-01	30462
2012-10-01	14695
2013-01-01	10543
2013-04-01	10514
2013-07-01	5571
2013-10-01	7223
2014-01-01	-12379
2014-04-01	-3048
2014-07-01	-3688
2014-10-01	134
2015-01-01	-5728
2015-04-01	-5224
2015-07-01	-5162
2015-10-01	-2036
2016-01-01	-4415
2016-04-01	28
2016-07-01	-2605
2016-10-01	6157
2017-01-01	-8550
2017-04-01	-1809
2017-07-01	5595
2017-10-01	-7744
2018-01-01	-6819
2018-04-01	-11075