Quarter	Millions of US Dollars
1971-01-01	61
1971-04-01	51
1971-10-01	20
1972-01-01	139
1972-04-01	11
1972-07-01	71
1972-10-01	114
1973-01-01	65
1973-04-01	114
1973-07-01	38
1973-10-01	114
1974-01-01	15
1974-07-01	37
1974-10-01	50
1975-01-01	131
1975-04-01	234
1975-07-01	118
1975-10-01	98
1976-01-01	39
1976-04-01	83
1976-07-01	375
1976-10-01	182
1977-01-01	95
1977-04-01	133
1977-07-01	562
1977-10-01	477
1978-01-01	401
1978-04-01	371
1978-07-01	265
1978-10-01	247
1979-01-01	247
1979-04-01	-18
1979-07-01	256
1979-10-01	55
1980-01-01	-19
1980-04-01	66
1980-07-01	56
1980-10-01	24
1981-01-01	33
1981-04-01	402
1981-07-01	452
1981-10-01	547
1982-01-01	230
1982-04-01	183
1982-07-01	-194
1982-10-01	193
1983-01-01	146
1983-04-01	78
1983-07-01	31
1983-10-01	-129
1984-01-01	10
1984-04-01	86
1984-07-01	-35
1984-10-01	1
1985-01-01	552
1985-04-01	458
1985-07-01	39
1985-10-01	-575
1986-01-01	34
1986-04-01	-19
1986-07-01	60
1986-10-01	-279
1987-01-01	-219
1987-04-01	-74
1987-07-01	-38
1987-10-01	-384
1988-01-01	-176
1988-04-01	-367
1988-07-01	-394
1988-10-01	-285
1989-01-01	-83
1989-04-01	-128
1989-07-01	-272
1989-10-01	265
1990-01-01	1276
1990-04-01	91
1990-07-01	295
1990-10-01	652
1991-01-01	151
1991-04-01	1414
1991-07-01	572
1991-10-01	1966
1992-01-01	845
1992-04-01	1292
1992-07-01	1531
1992-10-01	1885
1993-01-01	570
1993-04-01	2951
1993-07-01	3195
1993-10-01	7663
1994-01-01	4670
1994-04-01	2722
1994-07-01	2372
1994-10-01	1382
1995-01-01	-2709
1995-04-01	957
1995-07-01	3411
1995-10-01	2353
1996-01-01	3217
1996-04-01	6243
1996-07-01	3332
1996-10-01	10529
1997-01-01	4794
1997-04-01	8408
1997-07-01	9877
1997-10-01	1956
1998-01-01	3364
1998-04-01	4570
1998-07-01	-481
1998-10-01	-923
1999-01-01	-397
1999-04-01	2898
1999-07-01	274
1999-10-01	-306
2000-01-01	3257
2000-04-01	786
2000-07-01	1071
2000-10-01	-3356
2001-01-01	849
2001-04-01	1473
2001-07-01	700
2001-10-01	994
2002-01-01	251
2002-04-01	1271
2002-07-01	-2411
2002-10-01	1802
2003-01-01	1624
2003-04-01	242
2003-07-01	1725
2003-10-01	1754
2004-01-01	3971
2004-04-01	570
2004-07-01	-344
2004-10-01	491
2005-01-01	1505
2005-04-01	740
2005-07-01	5386
2005-10-01	3799
2006-01-01	5403
2006-04-01	3136
2006-07-01	5893
2006-10-01	8254
2007-01-01	2442
2007-04-01	20754
2007-07-01	1964
2007-10-01	7136
2008-01-01	66
2008-04-01	2910
2008-07-01	3351
2008-10-01	-5164
2009-01-01	-1344
2009-04-01	6086
2009-07-01	17775
2009-10-01	18511
2010-01-01	9900
2010-04-01	13440
2010-07-01	6646
2010-10-01	16303
2011-01-01	16493
2011-04-01	15302
2011-07-01	5901
2011-10-01	18588
2012-01-01	13193
2012-04-01	10137
2012-07-01	19186
2012-10-01	17875
2013-01-01	17115
2013-04-01	25191
2013-07-01	14603
2013-10-01	24559
2014-01-01	8269
2014-04-01	22464
2014-07-01	10904
2014-10-01	17600
2015-01-01	7552
2015-04-01	21677
2015-07-01	1672
2015-10-01	-1493
2016-01-01	19092
2016-04-01	3447
2016-07-01	7579
2016-10-01	11514
2017-01-01	8443
2017-04-01	7217
2017-07-01	20783
2017-10-01	10379
2018-01-01	6478
2018-04-01	9430