Quarter	Millions of US Dollars
1989-04-01	794
1989-07-01	2272
1989-10-01	1031
1990-01-01	1211
1990-04-01	3716
1990-07-01	491
1990-10-01	-4191
1991-01-01	-1210
1991-04-01	-3850
1991-07-01	1318
1991-10-01	-2727
1992-01-01	-8090
1992-04-01	2878
1992-07-01	-1325
1992-10-01	-7059
1993-01-01	-885
1993-04-01	4843
1993-07-01	2477
1993-10-01	3553
1994-01-01	283
1994-04-01	813
1994-07-01	1283
1994-10-01	-612
1995-01-01	3940
1995-04-01	1801
1995-07-01	1813
1995-10-01	850
1996-01-01	2315
1996-04-01	2950
1996-07-01	2543
1996-10-01	4243
1997-01-01	7973
1997-04-01	6107
1997-07-01	6203
1997-10-01	5801
1998-01-01	6530
1998-04-01	9923
1998-07-01	4735
1998-10-01	2848
1999-01-01	8106
1999-04-01	4382
1999-07-01	2277
1999-10-01	6702
2000-01-01	7058
2000-04-01	4588
2000-07-01	3029
2000-10-01	2803
2001-01-01	1131
2001-04-01	-2291
2001-07-01	915
2001-10-01	725
2002-01-01	-2433
2002-04-01	1313
2002-07-01	33
2002-10-01	-289
2003-01-01	3097
2003-04-01	-914
2003-07-01	1665
2003-10-01	1472
2004-01-01	3450
2004-04-01	4921
2004-07-01	3530
2004-10-01	8678
2005-01-01	9533
2005-04-01	4707
2005-07-01	8673
2005-10-01	9291
2006-01-01	17770
2006-04-01	8609
2006-07-01	7138
2006-10-01	13764
2007-01-01	4302
2007-04-01	10267
2007-07-01	-18141
2007-10-01	-11364
2008-01-01	4465
2008-04-01	-11795
2008-07-01	-12028
2008-10-01	-8263
2009-01-01	-7584
2009-04-01	-8693
2009-07-01	-9162
2009-10-01	-14364
2010-01-01	1308
2010-04-01	5364
2010-07-01	-3909
2010-10-01	5297
2011-01-01	4264
2011-04-01	-999
2011-07-01	3935
2011-10-01	507
2012-01-01	21791
2012-04-01	54
2012-07-01	3099
2012-10-01	2108
2013-01-01	10314
2013-04-01	5081
2013-07-01	10171
2013-10-01	2965
2014-01-01	11539
2014-04-01	7020
2014-07-01	6519
2014-10-01	-1413
2015-01-01	9801
2015-04-01	4149
2015-07-01	-2179
2015-10-01	2829
2016-01-01	1067
2016-04-01	9021
2016-07-01	9229
2016-10-01	-9328
2017-01-01	1209
2017-04-01	2170
2017-07-01	5835
2017-10-01	-2905
2018-01-01	1281