Quarter	Millions of US Dollars
2008-04-01	-2692
2008-07-01	-5904
2008-10-01	8811
2009-01-01	13827
2009-04-01	-19894
2009-07-01	20654
2009-10-01	-8579
2010-01-01	-18844
2010-04-01	-13695
2010-07-01	249638
2010-10-01	-44963
2011-01-01	6078
2011-04-01	-2004
2011-07-01	9036
2011-10-01	3036
2012-01-01	-5665
2012-04-01	-3515
2012-07-01	5846
2012-10-01	-1806
2013-01-01	-2171
2013-04-01	-4260
2013-07-01	5679
2013-10-01	3032
2014-01-01	5455
2014-04-01	-4932
2014-07-01	8534
2014-10-01	2251
2015-01-01	6232
2015-04-01	-3579
2015-07-01	3577
2015-10-01	4033
2016-01-01	13793
2016-04-01	-3603
2016-07-01	-488
2016-10-01	2971
2017-01-01	13275
2017-04-01	-6378
2017-07-01	3432
2017-10-01	9133
2018-01-01	-5466