Quarter	Millions of US Dollars
2002-01-01	538
2002-04-01	-2163
2002-07-01	9426
2002-10-01	-4020
2003-01-01	4127
2003-04-01	3
2003-07-01	1170
2003-10-01	3674
2004-01-01	2799
2004-04-01	-263
2004-07-01	3697
2004-10-01	455
2005-01-01	1430
2005-04-01	-3356
2005-07-01	776
2005-10-01	5805
2006-01-01	-4647
2006-04-01	-235
2006-07-01	-2509
2006-10-01	3457
2007-01-01	-3224
2007-04-01	-3967
2007-07-01	-11834
2007-10-01	4290
2008-01-01	45852
2008-04-01	-9558
2008-07-01	3343
2008-10-01	4015
2009-01-01	10777
2009-04-01	-20365
2009-07-01	20079
2009-10-01	-9449
2010-01-01	-16177
2010-04-01	-12067
2010-07-01	254554
2010-10-01	-39331
2011-01-01	1616
2011-04-01	1973
2011-07-01	7171
2011-10-01	5917
2012-01-01	-5975
2012-04-01	709
2012-07-01	5190
2012-10-01	-3227
2013-01-01	1238
2013-04-01	-3457
2013-07-01	6456
2013-10-01	10067
2014-01-01	13098
2014-04-01	-10000
2014-07-01	13050
2014-10-01	3055
2015-01-01	13937
2015-04-01	4979
2015-07-01	-1413
2015-10-01	8255
2016-01-01	25673
2016-04-01	-386
2016-07-01	-9265
2016-10-01	5516
2017-01-01	21171
2017-04-01	-8350
2017-07-01	-2026
2017-10-01	16007
2018-01-01	-10730