Quarter	Millions of US Dollars
1971-01-01	86
1971-04-01	51
1971-07-01	24
1971-10-01	51
1972-01-01	171
1972-04-01	78
1972-07-01	117
1972-10-01	221
1973-01-01	65
1973-04-01	300
1973-07-01	54
1973-10-01	414
1974-01-01	109
1974-04-01	424
1974-07-01	65
1974-10-01	72
1975-01-01	103
1975-04-01	326
1975-07-01	138
1975-10-01	111
1976-01-01	100
1976-04-01	201
1976-07-01	80
1976-10-01	239
1977-01-01	218
1977-04-01	195
1977-07-01	142
1977-10-01	243
1978-01-01	387
1978-04-01	478
1978-07-01	338
1978-10-01	411
1979-01-01	172
1979-04-01	173
1979-07-01	95
1979-10-01	-35
1980-01-01	-18
1980-04-01	-43
1980-07-01	109
1980-10-01	-90
1981-01-01	18
1981-04-01	-75
1981-10-01	-48
1982-01-01	-21
1982-04-01	56
1982-07-01	-66
1982-10-01	94
1983-01-01	134
1983-04-01	26
1983-07-01	-20
1983-10-01	-29
1984-01-01	43
1984-04-01	234
1984-07-01	139
1984-10-01	340
1985-01-01	75
1985-04-01	693
1985-07-01	-24
1985-10-01	-1083
1986-01-01	-209
1986-04-01	-83
1986-07-01	63
1986-10-01	-199
1987-01-01	-240
1987-04-01	-215
1987-07-01	-306
1987-10-01	-509
1988-01-01	-198
1988-04-01	-176
1988-07-01	-16
1988-10-01	18
1989-01-01	-230
1989-04-01	-294
1989-07-01	-29
1989-10-01	-80
1990-01-01	-182
1990-04-01	-764
1990-07-01	-338
1990-10-01	-320
1991-01-01	-246
1991-04-01	835
1991-07-01	-170
1991-10-01	114
1992-01-01	2409
1992-04-01	144
1992-07-01	-255
1992-10-01	-276
1993-01-01	-66
1993-04-01	-750
1993-07-01	6
1993-10-01	708
1994-01-01	742
1994-04-01	-422
1994-07-01	-32
1994-10-01	660
1995-01-01	406
1995-04-01	169
1995-07-01	268
1995-10-01	498
1996-01-01	161
1996-04-01	133
1996-07-01	358
1996-10-01	2329
1997-01-01	-54
1997-04-01	701
1997-07-01	1099
1997-10-01	273
1998-01-01	1797
1998-04-01	427
1998-07-01	338
1998-10-01	73
1999-01-01	686
1999-04-01	2825
1999-07-01	203
1999-10-01	94
2000-01-01	1341
2000-04-01	1840
2000-07-01	859
2000-10-01	-131
2001-01-01	486
2001-04-01	890
2001-07-01	1860
2001-10-01	-36
2002-01-01	634
2002-04-01	1637
2002-07-01	628
2002-10-01	-319
2003-01-01	374
2003-04-01	2202
2003-07-01	475
2003-10-01	146
2004-01-01	2351
2004-04-01	2511
2004-07-01	-273
2004-10-01	2296
2005-01-01	1158
2005-04-01	3187
2005-07-01	4963
2005-10-01	3584
2006-01-01	10549
2006-04-01	5397
2006-07-01	3394
2006-10-01	14412
2007-01-01	4951
2007-04-01	8902
2007-07-01	4669
2007-10-01	5008
2008-01-01	793
2008-04-01	7247
2008-07-01	1093
2008-10-01	-4118
2009-01-01	-794
2009-04-01	8161
2009-07-01	9556
2009-10-01	2192
2010-01-01	2503
2010-04-01	1946
2010-07-01	5024
2010-10-01	5109
2011-01-01	6013
2011-04-01	-2203
2011-07-01	-882
2011-10-01	12600
2012-01-01	4467
2012-04-01	-1219
2012-07-01	6133
2012-10-01	13479
2013-01-01	5045
2013-04-01	2271
2013-07-01	6310
2013-10-01	5917
2014-01-01	3655
2014-04-01	12096
2014-07-01	5025
2014-10-01	8475
2015-01-01	5014
2015-04-01	13234
2015-07-01	1667
2015-10-01	7629
2016-01-01	1876
2016-04-01	24422
2016-07-01	4643
2016-10-01	43448
2017-01-01	18674
2017-04-01	24718
2017-07-01	6954
2017-10-01	29347
2018-01-01	19666
2018-04-01	39901