Quarter	Millions of US Dollars
1971-01-01	15
1972-01-01	73
1972-07-01	28
1972-10-01	20
1973-01-01	50
1973-04-01	49
1973-07-01	10
1974-01-01	15
1974-07-01	8
1974-10-01	41
1975-01-01	160
1975-04-01	202
1975-07-01	231
1975-10-01	521
1976-01-01	494
1976-04-01	268
1976-07-01	244
1976-10-01	341
1977-01-01	814
1977-04-01	857
1977-07-01	184
1977-10-01	792
1978-01-01	854
1978-04-01	768
1978-07-01	250
1978-10-01	733
1979-01-01	652
1979-04-01	410
1979-07-01	496
1979-10-01	199
1980-01-01	340
1980-04-01	60
1980-07-01	-95
1980-10-01	-232
1981-01-01	-242
1981-04-01	-145
1981-07-01	-19
1981-10-01	113
1982-01-01	-509
1982-04-01	-157
1982-07-01	198
1982-10-01	-154
1983-01-01	-178
1983-04-01	-408
1983-07-01	92
1983-10-01	-258
1984-01-01	20
1984-04-01	-108
1984-07-01	172
1984-10-01	315
1985-01-01	19
1985-04-01	186
1985-07-01	824
1985-10-01	-610
1986-01-01	459
1986-04-01	843
1986-07-01	1797
1986-10-01	1162
1987-01-01	1645
1987-04-01	957
1987-07-01	-149
1987-10-01	-265
1988-01-01	1149
1988-04-01	1638
1988-07-01	607
1988-10-01	143
1989-01-01	1240
1989-04-01	93
1989-07-01	-174
1989-10-01	579
1990-01-01	-651
1990-04-01	-252
1990-07-01	-557
1990-10-01	-282
1991-01-01	-746
1991-04-01	-392
1991-07-01	642
1991-10-01	-25
1992-01-01	41
1992-04-01	1159
1992-07-01	-453
1992-10-01	-583
1993-01-01	-440
1993-04-01	314
1993-07-01	-393
1993-10-01	-726
1994-01-01	-488
1994-04-01	-243
1994-07-01	36
1994-10-01	-757
1995-01-01	-278
1995-04-01	-1014
1995-07-01	278
1995-10-01	-102
1996-01-01	1147
1996-04-01	498
1996-07-01	-776
1996-10-01	294
1997-01-01	684
1997-04-01	-197
1997-07-01	3597
1997-10-01	-215
1998-01-01	1769
1998-04-01	3731
1998-07-01	1288
1998-10-01	-95
1999-01-01	2323
1999-04-01	1458
1999-07-01	388
1999-10-01	-565
2000-01-01	3048
2000-04-01	3171
2000-07-01	2179
2000-10-01	72
2001-01-01	1181
2001-04-01	1208
2001-07-01	-1201
2001-10-01	1083
2002-01-01	1291
2002-04-01	1550
2002-07-01	-835
2002-10-01	1692
2003-01-01	3124
2003-04-01	2406
2003-07-01	1985
2003-10-01	2853
2004-01-01	1294
2004-04-01	2555
2004-07-01	-241
2004-10-01	5516
2005-01-01	1295
2005-04-01	2961
2005-07-01	355
2005-10-01	4072
2006-01-01	3926
2006-04-01	8754
2006-07-01	7178
2006-10-01	6427
2007-01-01	7578
2007-04-01	1220
2007-07-01	6871
2007-10-01	9601
2008-01-01	13991
2008-04-01	13004
2008-07-01	1731
2008-10-01	829
2009-01-01	4788
2009-04-01	2423
2009-07-01	2549
2009-10-01	259
2010-01-01	8687
2010-04-01	5064
2010-07-01	4729
2010-10-01	-335
2011-01-01	19536
2011-04-01	4665
2011-07-01	5552
2011-10-01	11137
2012-01-01	18827
2012-04-01	11887
2012-07-01	2297
2012-10-01	1568
2013-01-01	-360
2013-04-01	8253
2013-07-01	3401
2013-10-01	10089
2014-01-01	1357
2014-04-01	-7026
2014-07-01	1549
2014-10-01	2278
2015-01-01	4805
2015-04-01	-7050
2015-07-01	1215
2015-10-01	-5802
2016-01-01	-724
2016-04-01	43
2016-07-01	3208
2016-10-01	-10641
2017-01-01	10290
2017-04-01	-8185
2017-07-01	-4348
2017-10-01	128
2018-01-01	346
2018-04-01	-1457