Quarter	Millions of US Dollars
1977-04-01	50
1980-04-01	30
1982-04-01	-50
1982-07-01	19
1982-10-01	24
1983-01-01	21
1983-10-01	30
1984-01-01	121
1984-04-01	124
1984-07-01	41
1984-10-01	41
1985-01-01	38
1985-04-01	58
1985-07-01	129
1985-10-01	41
1986-01-01	82
1986-04-01	166
1986-07-01	125
1986-10-01	30
1987-01-01	98
1987-04-01	174
1987-07-01	346
1987-10-01	2
1988-01-01	469
1988-04-01	655
1988-10-01	670
1989-07-01	53
1989-10-01	-100
1990-07-01	-4
1990-10-01	-760
1991-01-01	-741
1991-04-01	-108
1991-07-01	-40
1991-10-01	216
1992-04-01	-93
1992-07-01	-226
1992-10-01	-36
1993-01-01	512
1993-04-01	-335
1993-07-01	925
1993-10-01	1000
1994-01-01	700
1994-04-01	-120
1994-07-01	1524
1994-10-01	440
1995-01-01	847
1995-04-01	1228
1995-07-01	-91
1995-10-01	1219
1996-01-01	380
1996-04-01	1366
1996-07-01	-272
1996-10-01	-99
1997-01-01	657
1997-04-01	842
1997-07-01	528
1997-10-01	741
1998-01-01	751
1998-04-01	192
1998-07-01	-6
1998-10-01	64
1999-01-01	-1362
1999-04-01	131
1999-07-01	-323
1999-10-01	2368
2000-01-01	216
2000-04-01	-35
2000-07-01	260
2000-10-01	602
2001-01-01	2007
2001-04-01	830
2001-07-01	1051
2001-10-01	1510
2002-01-01	2002
2002-04-01	1574
2002-07-01	566
2002-10-01	26
2003-01-01	3003
2003-04-01	1111
2003-07-01	1686
2003-10-01	953
2004-01-01	-2246
2004-04-01	3118
2004-07-01	-1331
2004-10-01	-207
2005-01-01	-10
2005-04-01	-351
2005-07-01	-470
2005-10-01	7315
2006-01-01	2985
2006-04-01	723
2006-07-01	2801
2006-10-01	5968
2007-01-01	-631
2007-04-01	12680
2007-07-01	-1782
2007-10-01	1950
2008-01-01	5625
2008-04-01	12297
2008-07-01	2475
2008-10-01	4769
2009-01-01	9952
2009-04-01	10744
2009-07-01	8941
2009-10-01	10316
2010-01-01	5051
2010-04-01	-3458
2010-07-01	374
2010-10-01	549
2011-01-01	407
2011-04-01	-9361
2011-07-01	-1712
2011-10-01	1738
2012-01-01	-7988
2012-04-01	-5224
2012-07-01	-6436
2012-10-01	4409
2013-01-01	-2615
2013-04-01	-7260
2013-07-01	-790
2013-10-01	-107
2014-01-01	-3544
2014-04-01	-8789
2014-07-01	3107
2014-10-01	-9068
2015-01-01	-1880
2015-04-01	721
2015-07-01	-1287
2015-10-01	-560
2016-01-01	43
2016-04-01	-1450
2016-07-01	1088
2016-10-01	-7252
2017-01-01	-4110
2017-04-01	1443
2017-07-01	744
2017-10-01	-1193
2018-01-01	2646
2018-04-01	1448