Quarter	Millions of US Dollars
1968-07-01	40
1973-10-01	2
1974-01-01	50
1975-01-01	20
1980-04-01	30
1981-04-01	20
1981-10-01	136
1982-04-01	30
1984-04-01	1
1984-07-01	21
1984-10-01	40
1985-01-01	150
1985-04-01	79
1985-07-01	21
1985-10-01	186
1986-01-01	294
1986-04-01	0
1986-10-01	45
1987-01-01	415
1987-07-01	58
1987-10-01	113
1988-01-01	74
1988-04-01	203
1988-07-01	337
1988-10-01	11
1989-04-01	250
1989-10-01	338
1990-01-01	101
1990-07-01	149
1990-10-01	230
1991-01-01	152
1991-04-01	-36
1991-07-01	293
1991-10-01	-6
1992-01-01	-335
1992-04-01	-51
1992-10-01	-194
1993-01-01	-401
1993-04-01	-136
1993-07-01	57
1993-10-01	270
1994-01-01	70
1994-04-01	231
1994-07-01	289
1994-10-01	-427
1995-01-01	-22
1995-04-01	-133
1995-07-01	192
1995-10-01	24
1996-01-01	315
1996-04-01	68
1996-07-01	350
1996-10-01	252
1997-01-01	294
1997-04-01	420
1997-07-01	913
1997-10-01	88
1998-01-01	348
1998-04-01	225
1998-07-01	-208
1998-10-01	-10
1999-01-01	50
1999-04-01	-401
1999-07-01	-199
1999-10-01	-405
2000-01-01	281
2000-04-01	-110
2000-07-01	-564
2001-01-01	-190
2001-04-01	-233
2001-07-01	-156
2002-01-01	120
2002-04-01	100
2002-07-01	-392
2002-10-01	-511
2003-01-01	-220
2003-07-01	100
2003-10-01	99
2004-01-01	798
2004-04-01	500
2004-07-01	1302
2004-10-01	1879
2005-01-01	2418
2005-04-01	525
2005-07-01	1198
2005-10-01	1582
2006-01-01	3472
2006-04-01	2199
2006-07-01	1195
2006-10-01	2362
2007-01-01	6315
2007-04-01	3640
2007-07-01	469
2007-10-01	3302
2008-01-01	347
2008-04-01	251
2008-07-01	1201
2008-10-01	618
2009-01-01	-1695
2009-04-01	513
2009-07-01	287
2009-10-01	3038
2010-01-01	-971
2010-04-01	-449
2010-07-01	-293
2010-10-01	2583
2011-01-01	1722
2011-04-01	4060
2011-07-01	1461
2011-10-01	-2385
2012-01-01	3516
2012-04-01	-1580
2012-07-01	1025
2012-10-01	1781
2013-01-01	3128
2013-04-01	7879
2013-07-01	1690
2013-10-01	3640
2014-01-01	2580
2014-04-01	4818
2014-07-01	6823
2014-10-01	1137
2015-01-01	728
2015-04-01	3516
2015-07-01	-776
2015-10-01	-1411
2016-01-01	-1200
2016-04-01	-1402
2016-07-01	2320
2016-10-01	-2193
2017-01-01	6437
2017-04-01	1215
2017-07-01	2049
2017-10-01	5465
2018-01-01	-604
2018-04-01	-3546