Quarter	Millions of US Dollars
2002-04-01	21010
2002-07-01	19047
2002-10-01	-6979
2003-01-01	16546
2003-04-01	5046
2003-07-01	19855
2003-10-01	-7014
2004-01-01	16644
2004-04-01	7681
2004-07-01	7849
2004-10-01	19952
2005-01-01	30651
2005-04-01	28026
2005-07-01	24721
2005-10-01	20284
2006-01-01	36585
2006-04-01	7152
2006-07-01	29670
2006-10-01	35013
2007-01-01	35011
2007-04-01	40921
2007-07-01	25708
2007-10-01	47409
2008-01-01	49314
2008-04-01	94431
2008-07-01	42049
2008-10-01	78576
2009-01-01	-364
2009-04-01	45096
2009-07-01	50329
2009-10-01	74298
2010-01-01	30022
2010-04-01	92567
2010-07-01	46835
2010-10-01	100391
2011-01-01	63569
2011-04-01	134771
2011-07-01	42679
2011-10-01	85980
2012-01-01	47205
2012-04-01	92074
2012-07-01	-8299
2012-10-01	78981
2013-01-01	-14142
2013-04-01	41818
2013-07-01	22349
2013-10-01	91291
2014-01-01	20416
2014-04-01	103671
2014-07-01	-1052
2014-10-01	110763
2015-01-01	58538
2015-04-01	51954
2015-07-01	65304
2015-10-01	57368
2016-01-01	39675
2016-04-01	40559
2016-07-01	34474
2016-10-01	84203
2017-01-01	50617
2017-04-01	25163
2017-07-01	39574
2017-10-01	34384
2018-01-01	34224