Quarter	Millions of US Dollars
1987-04-01	25
1987-07-01	-3
1987-10-01	74
1988-01-01	11
1988-04-01	19
1988-07-01	54
1988-10-01	34
1989-01-01	10
1989-04-01	85
1989-07-01	68
1989-10-01	38
1990-01-01	88
1990-04-01	69
1990-07-01	96
1990-10-01	-18
1991-01-01	-13
1991-04-01	43
1991-07-01	113
1991-10-01	22
1992-01-01	110
1992-04-01	24
1992-07-01	110
1992-10-01	-21
1993-01-01	72
1993-04-01	22
1993-07-01	144
1993-10-01	-17
1994-01-01	48
1994-04-01	50
1994-07-01	99
1994-10-01	-43
1995-01-01	-71
1995-04-01	6
1995-07-01	210
1995-10-01	-32
1996-01-01	77
1996-04-01	-1
1996-07-01	49
1996-10-01	-37
1997-01-01	110
1997-04-01	114
1997-07-01	106
1997-10-01	-194
1998-01-01	95
1998-04-01	63
1998-07-01	99
1998-10-01	-153
1999-01-01	-98
1999-04-01	11
1999-07-01	21
1999-10-01	-80
2000-01-01	-21
2000-04-01	-87
2000-07-01	-34
2000-10-01	-46
2001-01-01	28
2001-04-01	32
2001-07-01	49
2001-10-01	33
2002-01-01	66
2002-04-01	-142
2002-07-01	88
2002-10-01	-23
2003-01-01	68
2003-04-01	50
2003-07-01	244
2003-10-01	-111
2004-01-01	163
2004-04-01	-64
2004-07-01	92
2004-10-01	-135
2005-01-01	-81
2005-04-01	-106
2005-07-01	99
2005-10-01	105
2006-01-01	-258
2006-04-01	3
2006-07-01	250
2006-10-01	-26
2007-01-01	-128
2007-04-01	130
2007-07-01	63
2007-10-01	11
2008-01-01	21
2008-04-01	558
2008-07-01	334
2008-10-01	888
2009-01-01	310
2009-04-01	41
2009-07-01	445
2009-10-01	456
2010-01-01	-114
2010-04-01	2050
2010-07-01	534
2010-10-01	-90
2011-01-01	439
2011-04-01	11
2011-07-01	-90
2011-10-01	421
2012-01-01	93
2012-04-01	131
2012-07-01	-10
2012-10-01	67
2013-01-01	296
2013-04-01	-367
2013-07-01	187
2013-10-01	-66
2014-01-01	-125
2014-04-01	-33
2014-07-01	157
2014-10-01	286
2015-01-01	76
2015-04-01	-155
2015-07-01	373
2015-10-01	-125
2016-01-01	68
2016-04-01	-273
2016-07-01	317
2016-10-01	-353
2017-01-01	-304
2017-04-01	25
2017-07-01	-191
2017-10-01	-316
2018-01-01	-309