Quarter	Millions of US Dollars
1968-07-01	40
1972-04-01	25
1972-10-01	50
1973-01-01	30
1973-04-01	37
1973-10-01	20
1974-01-01	66
1974-04-01	17
1974-10-01	19
1975-01-01	45
1975-10-01	18
1976-04-01	13
1976-07-01	398
1976-10-01	52
1977-01-01	88
1977-04-01	37
1977-07-01	87
1977-10-01	46
1978-01-01	180
1978-04-01	146
1978-07-01	130
1978-10-01	128
1979-01-01	273
1979-04-01	108
1979-07-01	216
1980-04-01	51
1980-07-01	142
1980-10-01	47
1981-04-01	63
1981-07-01	116
1981-10-01	150
1982-01-01	445
1982-04-01	290
1982-07-01	37
1982-10-01	487
1983-01-01	53
1983-04-01	238
1983-07-01	1333
1983-10-01	179
1984-01-01	421
1984-04-01	42
1984-07-01	378
1984-10-01	1086
1985-01-01	735
1985-04-01	1540
1985-07-01	658
1985-10-01	2046
1986-01-01	1284
1986-04-01	534
1986-07-01	191
1986-10-01	285
1987-01-01	631
1987-04-01	231
1987-07-01	551
1987-10-01	473
1988-01-01	-27
1988-04-01	-77
1988-07-01	854
1988-10-01	373
1989-01-01	-76
1989-04-01	-23
1989-07-01	-110
1989-10-01	757
1990-01-01	236
1990-04-01	310
1990-07-01	536
1990-10-01	180
1991-01-01	724
1991-04-01	1681
1991-07-01	496
1991-10-01	501
1992-01-01	267
1992-04-01	64
1992-07-01	1601
1992-10-01	3377
1993-01-01	387
1993-04-01	1311
1993-07-01	1978
1993-10-01	5523
1994-01-01	4657
1994-04-01	4137
1994-07-01	4618
1994-10-01	1888
1995-01-01	1024
1995-04-01	2045
1995-07-01	6259
1995-10-01	2656
1996-01-01	5612
1996-04-01	7299
1996-07-01	11764
1996-10-01	14782
1997-01-01	8249
1997-04-01	12155
1997-07-01	11006
1997-10-01	3395
1998-01-01	-374
1998-04-01	6200
1998-07-01	-3544
1998-10-01	-940
1999-01-01	9
1999-04-01	234
1999-07-01	-3104
1999-10-01	-718
2000-01-01	2995
2000-04-01	-1621
2000-07-01	-1541
2000-10-01	443
2001-01-01	-3242
2001-04-01	1347
2001-07-01	-3036
2001-10-01	1274
2002-01-01	2975
2002-04-01	6358
2002-07-01	4180
2002-10-01	3606
2003-01-01	1412
2003-04-01	5162
2003-07-01	6668
2003-10-01	7106
2004-01-01	8550
2004-04-01	6689
2004-07-01	6967
2004-10-01	10817
2005-01-01	9282
2005-04-01	7107
2005-07-01	4792
2005-10-01	10572
2006-01-01	12134
2006-04-01	9168
2006-07-01	11557
2006-10-01	11875
2007-01-01	15994
2007-04-01	20519
2007-07-01	1088
2007-10-01	6306
2008-01-01	4566
2008-04-01	6452
2008-07-01	4852
2008-10-01	-12002
2009-01-01	2293
2009-04-01	9539
2009-07-01	15012
2009-10-01	5202
2010-01-01	7767
2010-04-01	5890
2010-07-01	15671
2010-10-01	26659
2011-01-01	22060
2011-04-01	33399
2011-07-01	11295
2011-10-01	10264
2012-01-01	33787
2012-04-01	32810
2012-07-01	22782
2012-10-01	23403
2013-01-01	33192
2013-04-01	46644
2013-07-01	30740
2013-10-01	50222
2014-01-01	45013
2014-04-01	63882
2014-07-01	38146
2014-10-01	67698
2015-01-01	29968
2015-04-01	53526
2015-07-01	13138
2015-10-01	32082
2016-01-01	778
2016-04-01	46979
2016-07-01	42577
2016-10-01	39816
2017-01-01	70839
2017-04-01	60409
2017-07-01	73128
2017-10-01	91028
2018-01-01	59327
2018-04-01	37811