Quarter	Millions of US Dollars
2000-04-01	13228
2000-07-01	9610
2000-10-01	17265
2001-01-01	5364
2001-04-01	7021
2001-07-01	10931
2001-10-01	12709
2002-01-01	25733
2002-04-01	22062
2002-07-01	42280
2002-10-01	13883
2003-01-01	-4766
2003-04-01	42982
2003-07-01	41725
2003-10-01	26203
2004-01-01	41250
2004-04-01	43522
2004-07-01	27514
2004-10-01	62975
2005-01-01	57454
2005-04-01	60978
2005-07-01	49647
2005-10-01	88299
2006-01-01	106740
2006-04-01	37933
2006-07-01	57140
2006-10-01	47977
2007-01-01	127443
2007-04-01	25044
2007-07-01	142490
2007-10-01	115454
2008-01-01	129561
2008-04-01	72684
2008-07-01	106888
2008-10-01	93313
2009-01-01	-18775
2009-04-01	115997
2009-07-01	104345
2009-10-01	152763
2010-01-01	80836
2010-04-01	182698
2010-07-01	104128
2010-10-01	23908
2011-01-01	-14100
2011-04-01	66633
2011-07-01	33095
2011-10-01	233138
2012-01-01	68917
2012-04-01	206732
2012-07-01	266679
2012-10-01	173852
2013-01-01	161479
2013-04-01	109962
2013-07-01	124845
2013-10-01	139577
2014-01-01	147511
2014-04-01	260325
2014-07-01	256320
2014-10-01	197975
2015-01-01	270576
2015-04-01	465659
2015-07-01	762575
2015-10-01	622245
2016-01-01	549634
2016-04-01	765573
2016-07-01	578050
2016-10-01	357500
2017-01-01	372894
2017-04-01	333727
2017-07-01	542373
2017-10-01	327063
2018-01-01	297371