Quarter	Millions of US Dollars
1981-10-01	25
1986-10-01	-25
1994-01-01	40
1994-04-01	40
1994-10-01	25
1995-01-01	0
1995-04-01	-25
1995-10-01	5
1996-04-01	5
1996-07-01	-10
1997-01-01	4831
1997-04-01	110
1998-01-01	5
1998-10-01	-590
1999-07-01	-1
1999-10-01	-1
2000-10-01	-3
2002-01-01	740
2002-04-01	-68
2002-10-01	-418
2003-01-01	732
2003-07-01	-36
2003-10-01	-410
2004-04-01	400
2004-10-01	806
2005-01-01	333
2005-07-01	750
2005-10-01	727
2006-01-01	0
2006-07-01	213
2006-10-01	979
2007-01-01	1417
2007-04-01	-102
2007-07-01	686
2007-10-01	14
2008-01-01	-1442
2008-10-01	-150
2009-01-01	1351
2009-04-01	25
2009-07-01	1070
2009-10-01	707
2010-01-01	568
2010-04-01	968
2010-07-01	940
2010-10-01	3606
2011-01-01	1128
2011-04-01	-10
2011-07-01	75
2011-10-01	320
2012-01-01	2712
2012-04-01	1347
2012-07-01	1545
2012-10-01	486
2013-01-01	2168
2013-04-01	3005
2013-07-01	-15
2013-10-01	671
2014-01-01	1100
2014-04-01	1063
2014-07-01	1922
2014-10-01	4379
2015-01-01	779
2015-04-01	905
2015-07-01	2022
2015-10-01	1214
2016-01-01	57
2016-04-01	-1100
2016-07-01	-540
2016-10-01	1934
2017-01-01	-444
2017-04-01	3550
2017-07-01	1090
2017-10-01	1236
2018-01-01	162
2018-04-01	242