Quarter	Millions of US Dollars
1999-01-01	1047
1999-04-01	308
1999-07-01	378
1999-10-01	-797
2000-01-01	-199
2000-04-01	-125
2000-07-01	479
2000-10-01	-200
2001-01-01	802
2001-04-01	424
2001-07-01	169
2001-10-01	52
2002-01-01	132
2002-04-01	604
2002-07-01	420
2002-10-01	680
2003-01-01	1129
2003-04-01	-376
2003-07-01	1439
2003-10-01	-2045
2004-01-01	503
2004-04-01	5670
2004-07-01	1222
2004-10-01	955
2005-01-01	3904
2005-04-01	5964
2005-07-01	5289
2005-10-01	-4896
2006-01-01	-1749
2006-04-01	-7114
2006-07-01	4190
2006-10-01	201
2007-01-01	4302
2007-04-01	7308
2007-07-01	360
2007-10-01	-5341
2008-01-01	-3116
2008-04-01	5184
2008-07-01	629
2008-10-01	1124
2009-01-01	1127
2009-04-01	-712
2009-07-01	-1671
2009-10-01	-886
2010-01-01	-59
2010-04-01	-69
2010-07-01	-3231
2010-10-01	1473
2011-01-01	1638
2011-04-01	13945
2011-07-01	5189
2011-10-01	-1589
2012-01-01	10630
2012-04-01	11121
2012-07-01	102
2012-10-01	-2535
2013-01-01	-2902
2013-04-01	6410
2013-07-01	9996
2013-10-01	-6821
2014-01-01	-3305
2014-04-01	7850
2014-07-01	654
2014-10-01	870
2015-01-01	-5409
2015-04-01	8903
2015-07-01	-2491
2015-10-01	-1586
2016-01-01	-3798
2016-04-01	9560
2016-07-01	-1583
2016-10-01	2416
2017-01-01	-16109
2017-04-01	14186
2017-07-01	7117
2017-10-01	-9280
2018-01-01	-4762