Quarter	Millions of US Dollars
1972-07-01	50
1975-04-01	40
1976-01-01	25
1977-01-01	30
1977-07-01	100
1977-10-01	45
1980-01-01	-25
1980-04-01	50
1981-01-01	-30
1981-04-01	-44
1984-07-01	25
1984-10-01	40
1985-01-01	170
1985-04-01	-50
1985-07-01	152
1985-10-01	-85
1986-01-01	188
1986-04-01	250
1986-07-01	72
1986-10-01	55
1987-01-01	274
1987-10-01	280
1988-01-01	315
1988-07-01	223
1988-10-01	272
1989-01-01	385
1989-04-01	102
1989-07-01	263
1989-10-01	105
1990-01-01	259
1990-04-01	120
1990-07-01	180
1990-10-01	364
1991-01-01	128
1991-04-01	54
1991-07-01	100
1991-10-01	840
1992-01-01	517
1992-04-01	52
1992-07-01	200
1992-10-01	-13
1993-01-01	1199
1993-04-01	641
1993-07-01	1256
1993-10-01	620
1994-01-01	964
1994-04-01	140
1994-07-01	509
1994-10-01	778
1995-01-01	-158
1995-04-01	713
1995-07-01	655
1995-10-01	657
1996-01-01	-92
1996-04-01	-49
1996-07-01	-533
1996-10-01	-383
1997-01-01	-18
1997-04-01	-117
1997-07-01	-127
1997-10-01	-360
1998-01-01	-328
1998-04-01	124
1998-07-01	219
1998-10-01	26
1999-01-01	-132
1999-04-01	1227
1999-07-01	-763
1999-10-01	147
2000-01-01	-701
2000-04-01	-528
2000-07-01	-351
2000-10-01	221
2001-01-01	0
2001-04-01	918
2001-07-01	-11
2001-10-01	-541
2002-01-01	-430
2002-04-01	-273
2002-07-01	-200
2003-01-01	533
2003-04-01	-250
2003-07-01	308
2003-10-01	-200
2004-01-01	-332
2004-04-01	348
2004-07-01	909
2004-10-01	1817
2005-01-01	2605
2005-04-01	1052
2005-07-01	614
2005-10-01	311
2006-01-01	3490
2006-04-01	-1190
2006-07-01	2181
2006-10-01	2086
2007-01-01	2710
2007-04-01	950
2007-07-01	131
2007-10-01	375
2008-01-01	1258
2008-04-01	3410
2008-07-01	578
2008-10-01	-240
2009-01-01	-1627
2009-04-01	-582
2009-07-01	1542
2009-10-01	618
2010-01-01	1130
2010-04-01	192
2010-07-01	-1759
2010-10-01	-588
2011-01-01	2600
2011-04-01	349
2011-07-01	165
2011-10-01	-1229
2012-01-01	-266
2012-04-01	-525
2012-07-01	-210
2012-10-01	-162
2013-01-01	1322
2013-04-01	301
2013-07-01	524
2013-10-01	3022
2014-01-01	1559
2014-04-01	-1498
2014-07-01	-3411
2014-10-01	1581
2015-01-01	-1636
2015-04-01	533
2015-07-01	15
2015-10-01	-576
2016-01-01	-709
2016-04-01	234
2016-07-01	-1611
2016-10-01	-528
2017-01-01	4
2017-04-01	-1454
2017-07-01	-1597
2017-10-01	947
2018-01-01	-1969
2018-04-01	-2578