Quarter	Millions of US Dollars
2004-04-01	962
2004-07-01	714
2004-10-01	29617
2005-01-01	2196
2005-04-01	3563
2005-07-01	3279
2005-10-01	5398
2006-01-01	5400
2006-04-01	1587
2006-07-01	5432
2006-10-01	7956
2007-01-01	5520
2007-04-01	8974
2007-07-01	3668
2007-10-01	2977
2008-01-01	11352
2008-04-01	5754
2008-07-01	6324
2008-10-01	2478
2009-01-01	1091
2009-04-01	6645
2009-07-01	16237
2009-10-01	14551
2010-01-01	2425
2010-04-01	1227
2010-07-01	15542
2010-10-01	15384
2011-01-01	15200
2011-04-01	11047
2011-07-01	145
2011-10-01	13535
2012-01-01	9778
2012-04-01	3929
2012-07-01	2862
2012-10-01	18319
2013-01-01	5343
2013-04-01	10064
2013-07-01	10363
2013-10-01	20547
2014-01-01	-1693
2014-04-01	9802
2014-07-01	818
2014-10-01	14942
2015-01-01	26290
2015-04-01	7724
2015-07-01	5215
2015-10-01	4976
2016-01-01	4925
2016-04-01	7091
2016-07-01	1477
2016-10-01	18394
2017-01-01	11239
2017-04-01	11897
2017-07-01	13710
2017-10-01	19343
2018-01-01	3641