Quarter	Millions of US Dollars
1972-01-01	49
1972-04-01	70
1972-07-01	10
1972-10-01	86
1973-04-01	136
1973-07-01	38
1973-10-01	295
1974-01-01	94
1974-04-01	363
1974-07-01	30
1974-10-01	72
1975-01-01	64
1975-04-01	55
1975-07-01	46
1976-01-01	61
1976-04-01	56
1976-07-01	37
1976-10-01	78
1977-01-01	117
1977-04-01	52
1977-07-01	43
1977-10-01	68
1978-01-01	64
1978-04-01	79
1978-07-01	62
1978-10-01	100
1983-10-01	-100
1985-04-01	-136
1985-07-01	-38
1985-10-01	-295
1986-01-01	-94
1986-04-01	-63
1986-07-01	-30
1986-10-01	-72
1987-01-01	-113
1987-04-01	-125
1987-07-01	-55
1987-10-01	-86
1988-01-01	-61
1988-04-01	-56
1988-07-01	-37
1988-10-01	-78
1989-01-01	-117
1989-04-01	-95
1989-10-01	-68
1990-01-01	-64
1990-04-01	-79
1990-07-01	-62
1991-04-01	949
1994-04-01	-300
1995-10-01	200
1996-10-01	200
1997-07-01	173
1998-04-01	-85
1998-10-01	250
1999-04-01	423
1999-10-01	163
2000-01-01	500
2001-10-01	-38
2002-01-01	351
2003-04-01	750
2003-10-01	750
2004-01-01	500
2004-04-01	1000
2004-10-01	750
2005-10-01	691
2006-04-01	-728
2006-10-01	1330
2007-07-01	-170
2007-10-01	-500
2009-01-01	979
2010-01-01	1573
2010-04-01	200
2011-01-01	124
2011-07-01	400
2012-01-01	1376
2012-04-01	-200
2012-07-01	-400
2013-01-01	2000
2013-04-01	-750
2014-01-01	1554
2015-10-01	-821
2016-01-01	1500
2016-10-01	-800
2017-01-01	2396
2017-07-01	3
2017-10-01	-3
2018-01-01	2000