Quarter	Millions of US Dollars
1996-01-01	73
1996-04-01	-729
1996-07-01	2824
1996-10-01	1377
1997-01-01	5579
1997-04-01	-1294
1997-07-01	1594
1997-10-01	578
1998-01-01	1807
1998-04-01	-389
1998-07-01	-156
1998-10-01	-1421
1999-01-01	544
1999-04-01	-2716
1999-07-01	1162
1999-10-01	890
2000-01-01	-390
2000-04-01	-1297
2000-07-01	1169
2000-10-01	2816
2001-01-01	3678
2001-04-01	-2722
2001-07-01	1722
2001-10-01	-928
2002-01-01	1991
2002-04-01	2026
2002-07-01	3415
2002-10-01	993
2003-01-01	4723
2003-04-01	2266
2003-07-01	1840
2003-10-01	605
2004-01-01	-552
2004-04-01	2084
2004-07-01	754
2004-10-01	-540
2005-01-01	-228
2005-04-01	1754
2005-07-01	4164
2005-10-01	164
2006-01-01	1817
2006-04-01	187
2006-07-01	5816
2006-10-01	4662
2007-01-01	-8066
2007-04-01	1506
2007-07-01	7413
2007-10-01	4061
2008-01-01	-291
2008-04-01	5619
2008-07-01	1900
2008-10-01	17425
2009-01-01	17412
2009-04-01	20479
2009-07-01	26541
2009-10-01	4312
2010-01-01	1744
2010-04-01	4615
2010-07-01	3297
2010-10-01	1741
2011-01-01	-1223
2011-04-01	-6099
2011-07-01	3411
2011-10-01	5748
2012-01-01	8346
2012-04-01	6336
2012-07-01	6050
2012-10-01	4327
2013-01-01	10926
2013-04-01	-6688
2013-07-01	4246
2013-10-01	-1715
2014-01-01	4052
2014-04-01	-6885
2014-07-01	1042
2014-10-01	2120
2015-01-01	2880
2015-04-01	-3813
2015-07-01	1539
2015-10-01	-130
2016-01-01	6645
2016-04-01	1947
2016-07-01	1001
2016-10-01	2750
2017-01-01	6400
2017-04-01	-1568
2017-07-01	2231
2017-10-01	2404
2018-01-01	5784