Quarter	Millions of US Dollars
1978-07-01	104
1979-01-01	37
1979-07-01	25
1980-07-01	46
1981-04-01	46
1982-04-01	200
1982-07-01	37
1982-10-01	75
1983-01-01	36
1983-07-01	292
1984-07-01	-34
1985-07-01	-32
1985-10-01	-44
1986-01-01	300
1988-07-01	-75
1988-10-01	161
1989-01-01	-36
1989-07-01	-134
1990-10-01	-75
1991-04-01	-72
1991-07-01	-7
1992-04-01	-178
1993-01-01	-54
1993-10-01	-428
1996-07-01	400
2001-01-01	-300
2004-01-01	1000
2005-04-01	1000
2005-10-01	1500
2006-01-01	2000
2006-04-01	0
2006-07-01	-400
2007-01-01	1500
2008-01-01	2000
2008-04-01	2200
2009-01-01	5000
2009-04-01	650
2009-07-01	359
2010-01-01	2000
2010-10-01	644
2011-04-01	2500
2012-01-01	3500
2012-04-01	2500
2012-10-01	764
2013-04-01	3000
2013-07-01	1000
2014-01-01	2700
2014-04-01	-1650
2014-07-01	2736
2014-10-01	73
2015-01-01	6031
2015-04-01	-998
2015-07-01	3432
2015-10-01	3503
2016-01-01	-891
2016-04-01	9156
2016-07-01	-1347
2016-10-01	3509
2017-01-01	-981
2017-04-01	947
2017-07-01	7397
2017-10-01	3008
2018-01-01	-1849
2018-04-01	3161