Quarter	Millions of US Dollars
1966-01-01	20
1967-10-01	15
1971-01-01	45
1971-04-01	23
1971-07-01	15
1972-01-01	120
1972-04-01	30
1972-07-01	25
1972-10-01	66
1973-01-01	73
1973-04-01	39
1973-10-01	46
1974-01-01	22
1974-04-01	50
1974-07-01	10
1974-10-01	73
1975-01-01	324
1975-04-01	376
1975-07-01	79
1975-10-01	335
1976-01-01	312
1976-04-01	162
1976-07-01	269
1976-10-01	439
1977-01-01	340
1977-04-01	374
1977-07-01	321
1977-10-01	434
1978-01-01	134
1978-04-01	440
1978-07-01	36
1978-10-01	76
1979-01-01	256
1979-04-01	826
1979-07-01	51
1979-10-01	389
1980-01-01	553
1980-04-01	895
1980-07-01	676
1980-10-01	593
1981-01-01	509
1981-04-01	278
1981-07-01	164
1981-10-01	425
1982-01-01	1128
1982-04-01	49
1982-07-01	340
1982-10-01	565
1983-01-01	1853
1983-04-01	-385
1983-07-01	29
1983-10-01	1123
1984-01-01	679
1984-04-01	1956
1984-07-01	893
1984-10-01	1681
1985-01-01	-1199
1985-04-01	2695
1985-07-01	53
1985-10-01	-1258
1986-01-01	924
1986-04-01	858
1986-07-01	841
1986-10-01	-274
1987-01-01	794
1987-04-01	249
1987-07-01	-111
1987-10-01	-383
1988-01-01	1529
1988-04-01	248
1988-07-01	580
1988-10-01	543
1989-01-01	1886
1989-04-01	271
1989-07-01	518
1989-10-01	2319
1990-01-01	1328
1990-04-01	-705
1990-07-01	551
1990-10-01	-188
1991-01-01	-64
1991-04-01	828
1991-07-01	230
1991-10-01	-1160
1992-01-01	-171
1992-04-01	1651
1992-07-01	1059
1992-10-01	1192
1993-01-01	3787
1993-04-01	-433
1993-07-01	7156
1993-10-01	4276
1994-01-01	5314
1994-04-01	6945
1994-07-01	4388
1994-10-01	1879
1995-01-01	-1113
1995-04-01	1297
1995-07-01	4232
1995-10-01	-900
1996-01-01	3568
1996-04-01	5509
1996-07-01	-932
1996-10-01	817
1997-01-01	837
1997-04-01	1281
1997-07-01	751
1997-10-01	-2491
1998-01-01	-4230
1998-04-01	3830
1998-07-01	-2128
1998-10-01	-4531
1999-01-01	-5519
1999-04-01	3934
1999-07-01	586
1999-10-01	468
2000-01-01	3652
2000-04-01	-741
2000-07-01	-107
2000-10-01	753
2001-01-01	521
2001-04-01	2337
2001-07-01	-2552
2001-10-01	689
2002-01-01	78
2002-04-01	4462
2002-07-01	1520
2002-10-01	-1822
2003-01-01	1872
2003-04-01	2738
2003-07-01	-402
2003-10-01	2279
2004-01-01	6656
2004-04-01	-880
2004-07-01	3229
2004-10-01	540
2005-01-01	6937
2005-04-01	14501
2005-07-01	2623
2005-10-01	433
2006-01-01	12368
2006-04-01	995
2006-07-01	139
2006-10-01	11182
2007-01-01	15626
2007-04-01	20721
2007-07-01	-1143
2007-10-01	10564
2008-01-01	-1458
2008-04-01	23916
2008-07-01	19419
2008-10-01	-9577
2009-01-01	23505
2009-04-01	30885
2009-07-01	20581
2009-10-01	10569
2010-01-01	28740
2010-04-01	-9653
2010-07-01	-586
2010-10-01	7992
2011-01-01	2903
2011-04-01	12947
2011-07-01	8308
2011-10-01	940
2012-01-01	17859
2012-04-01	13590
2012-07-01	8032
2012-10-01	19940
2013-01-01	17749
2013-04-01	3134
2013-07-01	16579
2013-10-01	-7588
2014-01-01	632
2014-04-01	7730
2014-07-01	6600
2014-10-01	10528
2015-01-01	-1182
2015-04-01	881
2015-07-01	7400
2015-10-01	9560
2016-01-01	829
2016-04-01	-7021
2016-07-01	3545
2016-10-01	7680
2017-01-01	12563
2017-04-01	2883
2017-07-01	1177
2017-10-01	-4077
2018-01-01	5161
2018-04-01	2994