Quarter	Millions of US Dollars
1972-01-01	20
1972-04-01	52
1972-10-01	20
1974-07-01	9
1976-10-01	48
1977-01-01	62
1977-07-01	25
1977-10-01	62
1978-01-01	91
1978-07-01	70
1978-10-01	22
1979-01-01	61
1980-04-01	-20
1980-07-01	25
1982-01-01	-14
1982-04-01	-42
1982-07-01	-25
1983-01-01	-51
1984-01-01	-20
1985-01-01	19
1985-10-01	-69
1986-01-01	-4
1986-07-01	26
1986-10-01	-87
1987-01-01	-3
1987-07-01	-26
1987-10-01	-2
1988-01-01	-92
1988-04-01	40
1988-10-01	-80
1989-01-01	-25
1990-01-01	-34
1990-07-01	-24
1991-04-01	87
1991-07-01	-32
1993-01-01	-41
1994-01-01	-112
1994-04-01	14
1994-07-01	5
1994-10-01	35
1995-04-01	-10
1995-07-01	300
1995-10-01	205
1996-01-01	1940
1996-04-01	-1839
1996-07-01	3222
1997-01-01	500
1997-04-01	134
1997-07-01	800
1997-10-01	400
1998-04-01	1263
1998-07-01	350
1998-10-01	-513
1999-01-01	1036
1999-04-01	0
1999-10-01	633
2000-04-01	574
2000-07-01	622
2000-10-01	629
2001-01-01	719
2001-04-01	905
2001-07-01	1057
2001-10-01	46
2002-01-01	653
2002-04-01	733
2002-07-01	791
2002-10-01	3349
2003-01-01	1368
2003-04-01	610
2003-07-01	-323
2003-10-01	-7
2004-01-01	-708
2004-04-01	1261
2004-07-01	3332
2004-10-01	2732
2005-01-01	-1118
2005-04-01	128
2005-07-01	11
2005-10-01	1836
2006-01-01	2254
2006-04-01	2329
2006-07-01	-467
2006-10-01	-124
2007-01-01	-250
2007-04-01	453
2007-07-01	338
2007-10-01	-123
2008-01-01	-144
2008-04-01	-134
2008-07-01	-193
2009-01-01	1972
2009-04-01	444
2009-07-01	-352
2009-10-01	-402
2010-01-01	1385
2010-04-01	650
2010-07-01	700
2010-10-01	1020
2011-01-01	609
2011-04-01	0
2011-07-01	1150
2011-10-01	3766
2012-01-01	-750
2012-04-01	3485
2012-07-01	1148
2012-10-01	3961
2013-01-01	-1225
2013-04-01	3299
2013-07-01	2368
2013-10-01	500
2014-01-01	300
2014-04-01	-252
2014-07-01	3000
2015-01-01	1729
2015-04-01	-250
2015-07-01	-500
2015-10-01	3550
2016-01-01	1282
2016-04-01	2000
2016-10-01	2795
2017-01-01	3700
2017-04-01	1422
2017-07-01	5350
2017-10-01	-2950
2018-01-01	300
2018-04-01	6762