Quarter	Millions of US Dollars
2006-01-01	5672
2006-04-01	4149
2006-07-01	-14851
2006-10-01	749
2007-01-01	-2886
2007-04-01	-2094
2007-07-01	-6426
2007-10-01	9238
2008-01-01	-659
2008-04-01	6604
2008-07-01	-3069
2008-10-01	7492
2009-01-01	-4301
2009-04-01	66690
2009-07-01	-971
2009-10-01	4798
2010-01-01	574
2010-04-01	4045
2010-07-01	3826
2010-10-01	4673
2011-01-01	888
2011-04-01	2684
2011-07-01	13
2011-10-01	3326
2012-01-01	2810
2012-04-01	2789
2012-07-01	-457
2012-10-01	5964
2013-01-01	724
2013-04-01	3159
2013-07-01	-951
2013-10-01	9068
2014-01-01	660
2014-04-01	3695
2014-07-01	1926
2014-10-01	7147
2015-01-01	1389
2015-04-01	3688
2015-07-01	1274
2015-10-01	2071
2016-01-01	525
2016-04-01	4685
2016-07-01	979
2016-10-01	3645
2017-01-01	-700
2017-04-01	5047
2017-07-01	4467
2017-10-01	1806
2018-01-01	3332