Quarter	Millions of US Dollars
2002-04-01	9055
2002-07-01	8723
2002-10-01	12576
2003-01-01	8942
2003-04-01	9624
2003-07-01	8079
2003-10-01	7953
2004-01-01	7016
2004-04-01	6052
2004-07-01	5064
2004-10-01	6404
2005-01-01	6654
2005-04-01	6043
2005-07-01	5284
2005-10-01	6057
2006-01-01	6365
2006-04-01	6273
2006-07-01	5734
2006-10-01	5830
2007-01-01	4659
2007-04-01	4548
2007-07-01	5107
2007-10-01	5684
2008-01-01	4190
2008-04-01	3789
2008-07-01	4156
2008-10-01	4741
2009-01-01	6207
2009-04-01	8272
2009-07-01	9893
2009-10-01	10354
2010-01-01	9598
2010-04-01	8808
2010-07-01	10633
2010-10-01	11645
2011-01-01	11782
2011-04-01	11234
2011-07-01	10596
2011-10-01	10929
2012-01-01	10403
2012-04-01	11376
2012-07-01	11735
2012-10-01	12690
2013-01-01	11842
2013-04-01	11674
2013-07-01	14333
2013-10-01	15473
2014-01-01	15198
2014-04-01	14018
2014-07-01	11537
2014-10-01	7156
2015-01-01	7248
2015-04-01	8386
2015-07-01	9112
2015-10-01	10102
2016-01-01	10973
2016-04-01	9602
2016-07-01	9061
2016-10-01	9035
2017-01-01	9023
2017-04-01	9736
2017-07-01	9399
2017-10-01	9933
2018-01-01	9682