Quarter	Millions of US Dollars
1971-01-01	15
1971-10-01	48
1972-01-01	79
1972-04-01	32
1972-07-01	120
1972-10-01	66
1973-01-01	71
1973-04-01	13
1973-07-01	69
1974-01-01	31
1974-04-01	2
1974-10-01	60
1975-01-01	146
1975-04-01	28
1975-07-01	155
1975-10-01	87
1976-01-01	67
1976-04-01	35
1976-07-01	65
1976-10-01	181
1977-01-01	58
1977-04-01	110
1977-07-01	73
1977-10-01	186
1978-01-01	326
1978-04-01	296
1978-07-01	153
1978-10-01	242
1979-01-01	301
1979-04-01	138
1979-07-01	29
1979-10-01	164
1980-01-01	-6
1980-04-01	70
1980-07-01	-24
1980-10-01	-8
1981-01-01	14
1981-04-01	259
1981-07-01	25
1981-10-01	205
1982-01-01	95
1982-04-01	225
1982-07-01	184
1982-10-01	151
1983-01-01	124
1983-04-01	185
1983-07-01	118
1983-10-01	-22
1984-01-01	292
1984-04-01	268
1984-07-01	231
1984-10-01	230
1985-01-01	279
1985-04-01	167
1985-07-01	158
1985-10-01	-166
1986-01-01	476
1986-04-01	425
1986-07-01	675
1986-10-01	468
1987-01-01	967
1987-04-01	450
1987-07-01	-142
1987-10-01	720
1988-01-01	638
1988-04-01	1308
1988-07-01	177
1988-10-01	1158
1989-01-01	1502
1989-04-01	615
1989-07-01	431
1989-10-01	937
1990-01-01	1175
1990-04-01	1338
1990-07-01	1535
1990-10-01	1752
1991-01-01	1164
1991-04-01	1403
1991-07-01	1080
1991-10-01	959
1992-01-01	1204
1992-04-01	3887
1992-07-01	2168
1992-10-01	2861
1993-01-01	2179
1993-04-01	853
1993-07-01	1867
1993-10-01	-901
1994-01-01	1365
1994-04-01	1465
1994-07-01	4034
1994-10-01	-350
1995-01-01	396
1995-04-01	-1160
1995-07-01	-162
1995-10-01	-1788
1996-01-01	1050
1996-04-01	-1213
1996-07-01	-1264
1996-10-01	1253
1997-01-01	1075
1997-04-01	-983
1997-07-01	-1272
1997-10-01	-1699
1998-01-01	-2618
1998-04-01	-5
1998-07-01	-335
1998-10-01	-2360
1999-01-01	-1046
1999-04-01	688
1999-07-01	1588
1999-10-01	-916
2000-01-01	-1971
2000-04-01	928
2000-07-01	-920
2000-10-01	-1073
2001-01-01	-694
2001-04-01	5268
2001-07-01	-1303
2001-10-01	-254
2002-01-01	1132
2002-04-01	-1566
2002-07-01	-565
2002-10-01	1480
2003-01-01	6837
2003-04-01	3130
2003-07-01	2150
2003-10-01	-24
2004-01-01	4584
2004-04-01	2244
2004-07-01	-2846
2004-10-01	4691
2005-01-01	-1055
2005-04-01	408
2005-07-01	2189
2005-10-01	2317
2006-01-01	3746
2006-04-01	3002
2006-07-01	-7671
2006-10-01	-6
2007-01-01	-1408
2007-04-01	2578
2007-07-01	-7799
2007-10-01	-3242
2008-01-01	-2688
2008-04-01	3304
2008-07-01	-3793
2008-10-01	977
2009-01-01	6262
2009-04-01	2655
2009-07-01	2772
2009-10-01	1913
2010-01-01	3741
2010-04-01	-925
2010-07-01	2411
2010-10-01	8239
2011-01-01	13619
2011-04-01	5428
2011-07-01	2069
2011-10-01	1090
2012-01-01	10907
2012-04-01	10725
2012-07-01	1074
2012-10-01	1048
2013-01-01	6655
2013-04-01	4678
2013-07-01	4866
2013-10-01	5387
2014-01-01	6346
2014-04-01	6949
2014-07-01	2673
2014-10-01	2727
2015-01-01	3414
2015-04-01	5872
2015-07-01	4851
2015-10-01	-3362
2016-01-01	-2334
2016-04-01	4545
2016-07-01	-9
2016-10-01	2904
2017-01-01	4552
2017-04-01	732
2017-07-01	2998
2017-10-01	4219
2018-01-01	7770
2018-04-01	-1334