Quarter	Millions of US Dollars
1998-01-01	127888
1998-04-01	39467
1998-07-01	146477
1998-10-01	-186457
1999-01-01	179886
1999-04-01	128486
1999-07-01	66991
1999-10-01	115340
2000-01-01	30723
2000-04-01	55951
2000-07-01	-40616
2000-10-01	145596
2001-01-01	238003
2001-04-01	173490
2001-07-01	1178
2001-10-01	41682
2002-01-01	120301
2002-04-01	200326
2002-07-01	42961
2002-10-01	109283
2003-01-01	260264
2003-04-01	134965
2003-07-01	-105739
2003-10-01	144365
2004-01-01	291116
2004-04-01	156436
2004-07-01	104907
2004-10-01	200384
2005-01-01	302261
2005-04-01	191691
2005-07-01	-61404
2005-10-01	134016
2006-01-01	-35564
2006-04-01	-74980
2006-07-01	108160
2006-10-01	25268
2007-01-01	16240
2007-04-01	-25054
2007-07-01	46906
2007-10-01	138256
2008-01-01	142535
2008-04-01	-124682
2008-07-01	-23546
2008-10-01	191259
2009-01-01	-143381
2009-04-01	160051
2009-07-01	61844
2009-10-01	116203
2010-01-01	37346
2010-04-01	443943
2010-07-01	118123
2010-10-01	17385
2011-01-01	-95433
2011-04-01	329495
2011-07-01	232996
2011-10-01	19037
2012-01-01	-38181
2012-04-01	289596
2012-07-01	101800
2012-10-01	154983
2013-01-01	51495
2013-04-01	6286
2013-07-01	91044
2013-10-01	80357
2014-01-01	54111
2014-04-01	153447
2014-07-01	16588
2014-10-01	95902
2015-01-01	110073
2015-04-01	1905
2015-07-01	11755
2015-10-01	-10351
2016-01-01	451185
2016-04-01	253559
2016-07-01	-133521
2016-10-01	-107899
2017-01-01	-15009
2017-04-01	13668
2017-07-01	18505
2017-10-01	82322
2018-01-01	26704