Quarter	Millions of US Dollars
1987-04-01	21
1987-07-01	23
1987-10-01	24
1988-01-01	35
1988-04-01	52
1988-07-01	45
1988-10-01	16
1989-01-01	60
1989-04-01	14
1989-07-01	37
1989-10-01	64
1990-01-01	63
1990-04-01	40
1990-07-01	66
1990-10-01	38
1991-01-01	135
1991-04-01	103
1991-07-01	117
1991-10-01	2
1992-01-01	187
1992-04-01	49
1992-07-01	120
1992-10-01	-53
1993-01-01	170
1993-04-01	55
1993-07-01	96
1993-10-01	33
1994-01-01	71
1994-04-01	24
1994-07-01	86
1994-10-01	53
1995-01-01	207
1995-04-01	98
1995-07-01	41
1995-10-01	0
1996-01-01	234
1996-04-01	114
1996-07-01	74
1996-10-01	108
1997-01-01	79
1997-04-01	103
1997-07-01	117
1997-10-01	118
1998-01-01	163
1998-04-01	61
1998-07-01	139
1998-10-01	108
1999-01-01	232
1999-04-01	124
1999-07-01	178
1999-10-01	115
2000-01-01	16
2000-04-01	204
2000-07-01	105
2000-10-01	201
2001-01-01	-200
2001-04-01	210
2001-07-01	170
2001-10-01	191
2002-01-01	258
2002-04-01	383
2002-07-01	79
2002-10-01	98
2003-01-01	458
2003-04-01	79
2003-07-01	335
2003-10-01	271
2004-01-01	164
2004-04-01	511
2004-07-01	85
2004-10-01	496
2005-01-01	257
2005-04-01	321
2005-07-01	759
2005-10-01	38
2006-01-01	515
2006-04-01	573
2006-07-01	259
2006-10-01	981
2007-01-01	340
2007-04-01	645
2007-07-01	588
2007-10-01	1381
2008-01-01	-572
2008-04-01	2542
2008-07-01	217
2008-10-01	-3203
2009-01-01	-325
2009-04-01	91
2009-07-01	100
2009-10-01	149
2010-01-01	130
2010-04-01	-11
2010-07-01	16
2010-10-01	104
2011-01-01	-40
2011-04-01	211
2011-07-01	56
2011-10-01	1084
2012-01-01	143
2012-04-01	96
2012-07-01	-116
2012-10-01	17
2013-01-01	115
2013-04-01	37
2013-07-01	66
2013-10-01	-27
2014-01-01	-31
2014-04-01	-42
2014-07-01	-145
2014-10-01	-67
2015-01-01	0
2015-04-01	4
2015-07-01	205
2015-10-01	62
2016-01-01	281
2016-04-01	65
2016-07-01	62
2016-10-01	73
2017-01-01	231
2017-04-01	304
2017-07-01	158
2017-10-01	-30
2018-01-01	454