Quarter	Millions of US Dollars
1971-01-01	30
1972-04-01	35
1974-04-01	24
1974-07-01	40
1974-10-01	20
1975-01-01	16
1975-04-01	234
1975-07-01	19
1976-01-01	108
1976-07-01	100
1976-10-01	97
1977-04-01	120
1977-07-01	106
1978-01-01	53
1978-07-01	24
1978-10-01	84
1979-01-01	100
1979-07-01	111
1979-10-01	-28
1980-01-01	-24
1980-04-01	-12
1980-07-01	10
1981-01-01	-108
1981-07-01	23
1981-10-01	28
1982-04-01	130
1982-07-01	-15
1982-10-01	700
1983-01-01	200
1983-04-01	472
1983-07-01	52
1983-10-01	161
1984-01-01	51
1984-04-01	100
1984-07-01	285
1984-10-01	378
1985-01-01	103
1985-04-01	121
1985-07-01	309
1985-10-01	-83
1986-01-01	516
1986-04-01	311
1986-07-01	530
1986-10-01	144
1987-01-01	399
1987-04-01	539
1987-07-01	95
1987-10-01	16
1988-01-01	-171
1988-04-01	331
1988-07-01	58
1988-10-01	745
1989-01-01	351
1989-04-01	-207
1989-07-01	-193
1989-10-01	79
1990-01-01	396
1990-04-01	-363
1990-07-01	205
1990-10-01	72
1991-01-01	578
1991-04-01	1560
1991-07-01	982
1991-10-01	369
1992-01-01	689
1992-04-01	-124
1992-07-01	95
1992-10-01	1301
1993-01-01	448
1993-04-01	1248
1993-07-01	2385
1993-10-01	253
1994-01-01	1802
1994-04-01	-79
1994-07-01	1012
1994-10-01	1740
1995-01-01	1516
1995-04-01	1818
1995-07-01	2372
1995-10-01	623
1996-01-01	2344
1996-04-01	4252
1996-07-01	1130
1996-10-01	289
1997-01-01	4366
1997-04-01	6103
1997-07-01	5149
1997-10-01	4734
1998-01-01	2649
1998-04-01	6773
1998-07-01	3104
1998-10-01	-817
1999-01-01	3047
1999-04-01	1451
1999-07-01	4382
1999-10-01	-917
2000-01-01	354
2000-04-01	6951
2000-07-01	1197
2000-10-01	11616
2001-01-01	907
2001-04-01	4428
2001-07-01	-1455
2001-10-01	2785
2002-01-01	460
2002-04-01	9659
2002-07-01	-882
2002-10-01	2819
2003-01-01	2277
2003-04-01	-1369
2003-07-01	7084
2003-10-01	12448
2004-01-01	31415
2004-04-01	9253
2004-07-01	17844
2004-10-01	19338
2005-01-01	9544
2005-04-01	3290
2005-07-01	24683
2005-10-01	685
2006-01-01	10162
2006-04-01	7992
2006-07-01	11130
2006-10-01	-3777
2007-01-01	22545
2007-04-01	15032
2007-07-01	20798
2007-10-01	-20420
2008-01-01	13932
2008-04-01	36708
2008-07-01	-4230
2008-10-01	-32412
2009-01-01	23897
2009-04-01	13483
2009-07-01	-160
2009-10-01	-10826
2010-01-01	13128
2010-04-01	-5703
2010-07-01	4559
2010-10-01	-14223
2011-01-01	3401
2011-04-01	-6177
2011-07-01	1897
2011-10-01	-3848
2012-01-01	10518
2012-04-01	-4970
2012-07-01	1848
2012-10-01	8590
2013-01-01	-14019
2013-04-01	-8565
2013-07-01	-13340
2013-10-01	1333
2014-01-01	5812
2014-04-01	23802
2014-07-01	22168
2014-10-01	1145
2015-01-01	9949
2015-04-01	23669
2015-07-01	7466
2015-10-01	-3517
2016-01-01	-2278
2016-04-01	25976
2016-07-01	1362
2016-10-01	-253
2017-01-01	-12222
2017-04-01	-3512
2017-07-01	2361
2017-10-01	3689
2018-01-01	11000
2018-04-01	662