Quarter	Millions of US Dollars
1972-07-01	50
1973-04-01	30
1974-04-01	52
1975-01-01	60
1975-04-01	80
1975-10-01	19
1976-01-01	42
1976-04-01	71
1976-07-01	17
1976-10-01	35
1977-01-01	70
1977-04-01	20
1977-07-01	150
1977-10-01	111
1978-04-01	77
1979-04-01	121
1979-07-01	56
1980-01-01	-25
1980-04-01	50
1980-07-01	12
1981-01-01	-30
1981-04-01	-122
1981-10-01	-35
1982-07-01	-34
1982-10-01	-20
1983-01-01	-60
1983-04-01	-60
1983-07-01	-35
1983-10-01	-17
1984-04-01	-70
1984-07-01	25
1984-10-01	-1
1985-01-01	170
1985-04-01	-22
1985-07-01	152
1985-10-01	-83
1986-01-01	173
1986-04-01	386
1986-07-01	72
1986-10-01	85
1987-01-01	404
1987-04-01	-33
1987-07-01	-4
1987-10-01	391
1988-01-01	766
1988-04-01	452
1988-07-01	541
1988-10-01	668
1989-01-01	893
1989-04-01	293
1989-07-01	1278
1989-10-01	497
1990-01-01	750
1990-04-01	268
1990-07-01	477
1990-10-01	682
1991-01-01	128
1991-04-01	321
1991-07-01	100
1991-10-01	1417
1992-01-01	802
1992-04-01	282
1992-07-01	1252
1992-10-01	900
1993-01-01	2317
1993-04-01	1272
1993-07-01	2176
1993-10-01	2211
1994-01-01	1360
1994-04-01	297
1994-07-01	5577
1994-10-01	6418
1995-01-01	-750
1995-04-01	392
1995-07-01	1580
1995-10-01	572
1996-01-01	338
1996-04-01	1977
1996-07-01	-2025
1996-10-01	241
1997-01-01	2256
1997-04-01	4509
1997-07-01	3195
1997-10-01	500
1998-01-01	2437
1998-04-01	5730
1998-07-01	5543
1998-10-01	-1914
1999-01-01	1251
1999-04-01	466
1999-07-01	-439
1999-10-01	2817
2000-01-01	1970
2000-04-01	3344
2000-07-01	21361
2000-10-01	-628
2001-01-01	933
2001-04-01	198
2001-07-01	30
2001-10-01	913
2002-01-01	1267
2002-04-01	650
2002-07-01	934
2002-10-01	1448
2003-01-01	5248
2003-04-01	393
2003-07-01	3354
2003-10-01	1401
2004-01-01	2706
2004-04-01	6226
2004-07-01	3028
2004-10-01	3182
2005-01-01	8710
2005-04-01	10914
2005-07-01	-3689
2005-10-01	5018
2006-01-01	9538
2006-04-01	-754
2006-07-01	5331
2006-10-01	11456
2007-01-01	10489
2007-04-01	5297
2007-07-01	147
2007-10-01	2797
2008-01-01	-1811
2008-04-01	13570
2008-07-01	6427
2008-10-01	-1841
2009-01-01	-727
2009-04-01	6233
2009-07-01	1691
2009-10-01	7606
2010-01-01	5198
2010-04-01	8863
2010-07-01	10363
2010-10-01	4706
2011-01-01	13492
2011-04-01	11793
2011-07-01	1013
2011-10-01	429
2012-01-01	11978
2012-04-01	21729
2012-07-01	21838
2012-10-01	32633
2013-01-01	8971
2013-04-01	18946
2013-07-01	8210
2013-10-01	26864
2014-01-01	-5882
2014-04-01	6656
2014-07-01	5462
2014-10-01	7647
2015-01-01	3498
2015-04-01	-1156
2015-07-01	-4931
2015-10-01	-18731
2016-01-01	935
2016-04-01	10038
2016-07-01	-3235
2016-10-01	9457
2017-01-01	5260
2017-04-01	9514
2017-07-01	9660
2017-10-01	9917
2018-01-01	4644
2018-04-01	-11695