Quarter	Millions of US Dollars
1971-01-01	25
1971-07-01	24
1971-10-01	31
1972-01-01	114
1972-04-01	135
1972-07-01	72
1972-10-01	247
1973-01-01	65
1973-04-01	172
1973-07-01	92
1973-10-01	427
1974-01-01	110
1974-04-01	380
1974-07-01	30
1974-10-01	97
1975-01-01	164
1975-04-01	129
1975-07-01	46
1975-10-01	25
1976-01-01	111
1976-04-01	178
1976-07-01	87
1976-10-01	188
1977-01-01	312
1977-04-01	478
1977-07-01	273
1977-10-01	503
1978-01-01	975
1978-04-01	563
1978-07-01	317
1978-10-01	661
1979-01-01	522
1979-04-01	190
1979-07-01	378
1979-10-01	182
1980-01-01	-75
1980-04-01	285
1980-07-01	301
1980-10-01	74
1981-01-01	9
1981-04-01	196
1981-07-01	133
1981-10-01	257
1982-01-01	418
1982-04-01	-146
1982-07-01	252
1982-10-01	362
1983-01-01	-347
1983-04-01	190
1983-07-01	1291
1983-10-01	-5
1984-01-01	393
1984-04-01	44
1984-07-01	95
1984-10-01	733
1985-01-01	-32
1985-04-01	840
1985-07-01	-31
1985-10-01	348
1986-01-01	152
1986-04-01	-78
1986-07-01	-201
1986-10-01	-419
1987-01-01	-381
1987-04-01	-144
1987-07-01	-203
1987-10-01	-236
1988-01-01	170
1988-04-01	-499
1988-07-01	-54
1988-10-01	760
1989-01-01	-70
1989-04-01	-249
1989-07-01	1276
1989-10-01	-93
1990-01-01	34380
1990-04-01	179
1990-07-01	-131
1990-10-01	15141
1991-01-01	268
1991-04-01	1376
1991-07-01	124
1991-10-01	952
1992-01-01	2679
1992-04-01	62
1992-07-01	1302
1992-10-01	3046
1993-01-01	1323
1993-04-01	18340
1993-07-01	160
1993-10-01	12343
1994-01-01	3263
1994-04-01	41940
1994-07-01	7282
1994-10-01	7144
1995-01-01	5165
1995-04-01	2587
1995-07-01	6057
1995-10-01	4034
1996-01-01	7151
1996-04-01	5346
1996-07-01	10522
1996-10-01	7252
1997-01-01	15116
1997-04-01	13444
1997-07-01	6374
1997-10-01	2872
1998-01-01	8703
1998-04-01	16462
1998-07-01	7768
1998-10-01	-21976
1999-01-01	6591
1999-04-01	15339
1999-07-01	3169
1999-10-01	11647
2000-01-01	15809
2000-04-01	4660
2000-07-01	38882
2000-10-01	-322
2001-01-01	10422
2001-04-01	-1763
2001-07-01	2353
2001-10-01	-3085
2002-01-01	8066
2002-04-01	-2723
2002-07-01	3886
2002-10-01	-1000
2003-01-01	-1290
2003-04-01	854
2003-07-01	3525
2003-10-01	3604
2004-01-01	9174
2004-04-01	6301
2004-07-01	4004
2004-10-01	9103
2005-01-01	13860
2005-04-01	-15706
2005-07-01	-2622
2005-10-01	8585
2006-01-01	14580
2006-04-01	-19810
2006-07-01	4696
2006-10-01	6157
2007-01-01	6537
2007-04-01	527
2007-07-01	-2175
2007-10-01	3479
2008-01-01	-7225
2008-04-01	12149
2008-07-01	-1545
2008-10-01	-7902
2009-01-01	8203
2009-04-01	8963
2009-07-01	9213
2009-10-01	21270
2010-01-01	11961
2010-04-01	14968
2010-07-01	14117
2010-10-01	12321
2011-01-01	10900
2011-04-01	9813
2011-07-01	11495
2011-10-01	11559
2012-01-01	19496
2012-04-01	26928
2012-07-01	11948
2012-10-01	19233
2013-01-01	1573
2013-04-01	5878
2013-07-01	20680
2013-10-01	32134
2014-01-01	893
2014-04-01	10386
2014-07-01	11240
2014-10-01	7798
2015-01-01	17436
2015-04-01	4304
2015-07-01	10150
2015-10-01	-4666
2016-01-01	17606
2016-04-01	59143
2016-07-01	6382
2016-10-01	59336
2017-01-01	39118
2017-04-01	43084
2017-07-01	24006
2017-10-01	47596
2018-01-01	43302
2018-04-01	35387