Quarter	Millions of US Dollars
1971-01-01	45
1971-07-01	20
1972-01-01	82
1972-04-01	41
1972-07-01	20
1972-10-01	41
1973-01-01	12
1973-07-01	80
1973-10-01	39
1974-01-01	50
1975-01-01	22
1975-04-01	25
1976-10-01	42
1977-01-01	135
1977-04-01	128
1977-07-01	100
1979-04-01	15
1980-07-01	40
1982-01-01	-21
1983-10-01	50
1985-04-01	-64
1985-07-01	-50
1985-10-01	-314
1986-01-01	70
1986-04-01	-13
1986-07-01	10
1986-10-01	-47
1987-01-01	-18
1987-04-01	362
1987-07-01	31
1987-10-01	-5
1988-01-01	-24
1988-07-01	100
1988-10-01	77
1989-01-01	86
1989-04-01	60
1989-07-01	90
1989-10-01	75
1990-01-01	-3
1990-07-01	-100
1990-10-01	-22
1991-07-01	-100
1992-01-01	-2
1992-04-01	-75
1992-07-01	200
1992-10-01	100
1993-01-01	150
1993-04-01	5
1993-07-01	140
1993-10-01	379
1994-01-01	1166
1994-04-01	-23
1994-07-01	-9
1994-10-01	369
1995-01-01	157
1995-04-01	-191
1995-07-01	594
1995-10-01	1997
1996-01-01	421
1996-04-01	569
1996-07-01	1652
1996-10-01	1576
1997-01-01	1005
1997-04-01	52
1997-07-01	8
1997-10-01	-74
1998-01-01	2189
1998-04-01	1628
1998-07-01	2414
1998-10-01	148
1999-01-01	144
1999-04-01	-79
1999-07-01	463
1999-10-01	-305
2000-01-01	622
2000-04-01	1634
2000-07-01	-1039
2000-10-01	3189
2001-01-01	809
2001-04-01	779
2001-07-01	734
2001-10-01	-482
2002-01-01	-1645
2002-04-01	1513
2002-07-01	-531
2002-10-01	-1191
2003-01-01	-711
2003-04-01	-263
2003-07-01	-950
2003-10-01	3867
2004-01-01	-657
2004-04-01	168
2004-07-01	784
2004-10-01	261
2005-01-01	3458
2005-04-01	483
2005-07-01	-88
2005-10-01	1096
2006-01-01	-224
2006-04-01	1839
2006-07-01	3335
2006-10-01	-1873
2007-01-01	3241
2007-04-01	4415
2007-07-01	-383
2007-10-01	-1117
2008-01-01	992
2008-04-01	6262
2008-07-01	2583
2008-10-01	-898
2009-01-01	6943
2009-04-01	2986
2009-07-01	1433
2009-10-01	3206
2010-01-01	1713
2010-04-01	-293
2010-07-01	4937
2010-10-01	4126
2011-01-01	1979
2011-04-01	3836
2011-07-01	-359
2011-10-01	350
2012-01-01	-1665
2012-04-01	4227
2012-07-01	2238
2012-10-01	1080
2013-01-01	913
2013-04-01	4773
2013-07-01	3239
2013-10-01	581
2014-01-01	2642
2014-04-01	-1836
2014-07-01	-593
2014-10-01	2781
2015-01-01	581
2015-04-01	509
2015-07-01	-488
2015-10-01	829
2016-01-01	429
2016-04-01	-1647
2016-07-01	2071
2016-10-01	3348
2017-01-01	-2190
2017-04-01	-82
2017-07-01	2270
2017-10-01	353
2018-01-01	1164
2018-04-01	7135