Quarter	Millions of US Dollars
2005-04-01	3775
2005-07-01	2983
2005-10-01	4847
2006-01-01	5976
2006-04-01	5166
2006-07-01	4601
2006-10-01	8780
2007-01-01	14381
2007-04-01	7296
2007-07-01	4122
2007-10-01	12384
2008-01-01	7603
2008-04-01	6922
2008-07-01	-3745
2008-10-01	-2857
2009-01-01	12441
2009-04-01	5341
2009-07-01	8774
2009-10-01	5879
2010-01-01	10262
2010-04-01	6556
2010-07-01	10028
2010-10-01	6151
2011-01-01	7983
2011-04-01	5229
2011-07-01	15882
2011-10-01	-902
2012-01-01	9906
2012-04-01	-3636
2012-07-01	-6679
2012-10-01	7429
2013-01-01	14592
2013-04-01	-7493
2013-07-01	-3131
2013-10-01	989
2014-01-01	5904
2014-04-01	4040
2014-07-01	40
2014-10-01	3361
2015-01-01	2171
2015-04-01	7170
2015-07-01	1362
2015-10-01	4719
2016-01-01	39200
2016-04-01	-4079
2016-07-01	2234
2016-10-01	-8502
2017-01-01	10775
2017-04-01	-4208
2017-07-01	2311
2017-10-01	6014
2018-01-01	1658