Quarter	Millions of US Dollars
1987-04-01	0
1987-07-01	0
1987-10-01	0
1988-01-01	0
1988-04-01	0
1988-07-01	0
1988-10-01	0
1989-01-01	0
1989-04-01	0
1989-07-01	0
1989-10-01	0
1990-01-01	0
1990-04-01	0
1990-07-01	0
1990-10-01	0
1991-01-01	0
1991-04-01	0
1991-07-01	0
1991-10-01	0
1992-01-01	0
1992-04-01	0
1992-07-01	0
1992-10-01	0
1993-01-01	0
1993-04-01	0
1993-07-01	0
1993-10-01	0
1994-01-01	0
1994-04-01	9
1994-07-01	13
1994-10-01	5
1995-01-01	4
1995-04-01	-1
1995-07-01	12
1995-10-01	6
1996-01-01	0
1996-04-01	17
1996-07-01	6
1996-10-01	5
1997-01-01	13
1997-04-01	13
1997-07-01	1
1997-10-01	17
1998-01-01	10
1998-04-01	14
1998-07-01	51
1998-10-01	55
1999-01-01	8
1999-04-01	23
1999-07-01	16
1999-10-01	57
2000-01-01	-12
2000-04-01	-4
2000-07-01	-11
2000-10-01	-6
2001-01-01	1
2001-04-01	19
2001-07-01	-1
2001-10-01	64
2002-01-01	16
2002-04-01	-2
2002-07-01	49
2002-10-01	88
2003-01-01	0
2003-04-01	45
2003-07-01	51
2003-10-01	252
2004-01-01	-39
2004-04-01	52
2004-07-01	138
2004-10-01	489
2005-01-01	10
2005-04-01	624
2005-07-01	74
2005-10-01	664
2006-01-01	45
2006-04-01	716
2006-07-01	-58
2006-10-01	641
2007-01-01	-388
2007-04-01	892
2007-07-01	605
2007-10-01	388
2008-01-01	-683
2008-04-01	97
2008-07-01	181
2008-10-01	-244
2009-01-01	111
2009-04-01	-499
2009-07-01	-321
2009-10-01	-311
2010-01-01	-550
2010-04-01	40
2010-07-01	0
2010-10-01	35
2011-01-01	86
2011-04-01	-29
2011-07-01	-93
2011-10-01	31
2012-01-01	-57
2012-04-01	-45
2012-07-01	-29
2012-10-01	47
2013-01-01	108
2013-04-01	176
2013-07-01	-232
2013-10-01	230
2014-01-01	-79
2014-04-01	0
2014-07-01	253
2014-10-01	255
2015-01-01	8
2015-04-01	212
2015-07-01	-15
2015-10-01	86
2016-01-01	26
2016-04-01	90
2016-07-01	42
2016-10-01	134
2017-01-01	38
2017-04-01	111
2017-07-01	-89
2017-10-01	48
2018-01-01	134