Quarter	Millions of US Dollars
1968-07-01	40
1969-01-01	70
1969-04-01	15
1972-07-01	79
1972-10-01	9
1973-07-01	43
1974-01-01	19
1974-04-01	27
1974-07-01	100
1974-10-01	152
1975-01-01	189
1975-04-01	213
1975-07-01	106
1975-10-01	36
1976-01-01	71
1976-04-01	251
1976-07-01	69
1976-10-01	28
1977-01-01	32
1977-04-01	60
1977-07-01	24
1977-10-01	49
1978-01-01	25
1978-04-01	66
1978-07-01	159
1978-10-01	11
1979-01-01	362
1979-04-01	143
1979-07-01	-188
1979-10-01	-20
1980-01-01	10
1980-04-01	185
1980-07-01	57
1980-10-01	67
1981-01-01	-40
1981-04-01	-45
1981-07-01	51
1981-10-01	99
1982-01-01	17
1982-04-01	16
1982-07-01	41
1982-10-01	162
1983-01-01	106
1983-04-01	-47
1983-07-01	194
1983-10-01	101
1984-01-01	-15
1984-04-01	-16
1984-07-01	-41
1984-10-01	146
1985-01-01	29
1985-04-01	26
1985-07-01	36
1985-10-01	91
1986-01-01	261
1986-04-01	469
1986-07-01	116
1986-10-01	274
1987-01-01	913
1987-04-01	424
1987-07-01	194
1987-10-01	-38
1988-01-01	261
1988-04-01	546
1988-07-01	688
1988-10-01	633
1989-01-01	176
1989-04-01	38
1989-07-01	193
1989-10-01	513
1990-01-01	245
1990-04-01	19
1990-07-01	292
1990-10-01	520
1991-01-01	90
1991-04-01	295
1991-07-01	36
1991-10-01	29
1992-01-01	-405
1992-04-01	-362
1992-07-01	-107
1992-10-01	276
1993-01-01	-129
1993-04-01	-209
1993-07-01	1702
1993-10-01	364
1994-01-01	-548
1994-04-01	964
1994-07-01	-127
1994-10-01	-594
1995-01-01	-580
1995-04-01	799
1995-07-01	-287
1995-10-01	-121
1996-01-01	-26
1996-04-01	573
1996-07-01	856
1996-10-01	660
1997-01-01	-695
1997-04-01	449
1997-07-01	1031
1997-10-01	71
1998-01-01	-98
1998-04-01	2047
1998-07-01	582
1998-10-01	3294
1999-01-01	196
1999-04-01	3867
1999-07-01	4853
1999-10-01	2185
2000-01-01	875
2000-04-01	7209
2000-07-01	8225
2000-10-01	11064
2001-01-01	2301
2001-04-01	773
2001-07-01	3361
2001-10-01	3064
2002-01-01	138
2002-04-01	-2069
2002-07-01	3
2002-10-01	-1314
2003-01-01	-430
2003-04-01	7356
2003-07-01	-1253
2003-10-01	5248
2004-01-01	-1970
2004-04-01	-2574
2004-07-01	-5060
2004-10-01	-1535
2005-01-01	-2128
2005-04-01	-26
2005-07-01	-3887
2005-10-01	-847
2006-01-01	4038
2006-04-01	18
2006-07-01	-955
2006-10-01	3484
2007-01-01	-1959
2007-04-01	1434
2007-07-01	-4980
2007-10-01	3185
2008-01-01	3260
2008-04-01	-4269
2008-07-01	862
2008-10-01	2080
2009-01-01	4079
2009-04-01	-1669
2009-07-01	377
2009-10-01	1279
2010-01-01	420
2010-04-01	1428
2010-07-01	2145
2010-10-01	4290
2011-01-01	-1497
2011-04-01	2417
2011-07-01	12977
2011-10-01	5112
2012-01-01	6249
2012-04-01	5392
2012-07-01	2117
2012-10-01	5149
2013-01-01	4541
2013-04-01	6044
2013-07-01	675
2013-10-01	2097
2014-01-01	2382
2014-04-01	375
2014-07-01	-263
2014-10-01	4260
2015-01-01	2143
2015-04-01	4549
2015-07-01	375
2015-10-01	898
2016-01-01	5188
2016-04-01	15675
2016-07-01	9548
2016-10-01	-5421
2017-01-01	5982
2017-04-01	5414
2017-07-01	9095
2017-10-01	7588
2018-01-01	9069
2018-04-01	970