Quarter	Millions of US Dollars
1971-01-01	15
1972-07-01	9
1973-01-01	21
1974-07-01	8
1975-01-01	43
1975-04-01	82
1975-07-01	50
1975-10-01	170
1976-01-01	151
1976-04-01	52
1976-07-01	92
1976-10-01	110
1977-01-01	183
1977-04-01	119
1977-07-01	26
1977-10-01	139
1978-01-01	94
1978-04-01	24
1978-07-01	76
1978-10-01	50
1979-01-01	81
1979-07-01	115
1980-01-01	-27
1980-07-01	-20
1980-10-01	-17
1981-04-01	2
1981-07-01	43
1981-10-01	-17
1982-04-01	88
1982-07-01	40
1982-10-01	50
1983-01-01	122
1983-10-01	-37
1984-01-01	25
1984-04-01	63
1984-07-01	48
1984-10-01	5
1985-01-01	18
1985-04-01	-61
1985-07-01	343
1985-10-01	-84
1986-01-01	188
1986-04-01	364
1986-07-01	248
1986-10-01	-68
1987-01-01	588
1987-04-01	103
1987-07-01	-64
1987-10-01	37
1988-01-01	544
1988-04-01	388
1988-07-01	321
1988-10-01	36
1989-01-01	251
1989-04-01	-179
1989-07-01	-82
1989-10-01	57
1990-01-01	-9
1990-04-01	-10
1990-07-01	-470
1990-10-01	-150
1991-01-01	-261
1991-04-01	-49
1991-07-01	137
1991-10-01	37
1992-01-01	-293
1992-04-01	333
1992-07-01	-372
1992-10-01	-50
1993-01-01	-34
1993-04-01	-427
1993-07-01	-131
1993-10-01	-78
1994-01-01	-350
1994-07-01	200
1994-10-01	193
1995-01-01	-372
1995-04-01	-176
1995-07-01	-51
1995-10-01	-100
1996-01-01	-37
1996-04-01	624
1996-07-01	233
1996-10-01	878
1997-01-01	517
1997-04-01	-6
1997-07-01	1142
1997-10-01	256
1998-01-01	308
1998-04-01	1624
1998-07-01	125
1998-10-01	1858
1999-01-01	1439
1999-04-01	473
1999-07-01	295
1999-10-01	534
2000-01-01	611
2000-04-01	1039
2000-07-01	1727
2000-10-01	-481
2001-01-01	-1231
2001-04-01	110
2001-07-01	-1276
2001-10-01	585
2002-01-01	552
2002-04-01	77
2002-07-01	-209
2002-10-01	736
2003-01-01	-230
2003-04-01	-144
2003-07-01	33
2003-10-01	87
2004-01-01	288
2004-04-01	280
2004-07-01	-285
2004-10-01	241
2005-01-01	-298
2005-04-01	185
2005-07-01	-93
2005-10-01	-94
2006-01-01	-422
2006-04-01	-268
2006-07-01	2381
2006-10-01	-477
2007-01-01	-121
2007-04-01	1046
2007-07-01	39
2007-10-01	-307
2008-01-01	-135
2008-04-01	170
2008-07-01	-44
2008-10-01	-361
2009-01-01	3184
2009-04-01	3797
2009-07-01	494
2009-10-01	643
2010-01-01	331
2010-04-01	-538
2010-07-01	1789
2010-10-01	315
2011-01-01	359
2011-04-01	162
2011-07-01	51
2011-10-01	1350
2012-01-01	257
2012-04-01	2360
2012-07-01	1424
2012-10-01	3142
2013-01-01	-1136
2013-04-01	4835
2013-07-01	3744
2013-10-01	4610
2014-01-01	345
2014-04-01	-479
2014-07-01	-16
2014-10-01	759
2015-01-01	4159
2015-04-01	-212
2015-07-01	-96
2015-10-01	-1074
2016-01-01	120
2016-04-01	357
2016-07-01	818
2016-10-01	348
2017-01-01	1065
2017-04-01	-1050
2017-07-01	-3055
2017-10-01	-3445
2018-01-01	-832
2018-04-01	28