Quarter	Millions of US Dollars
1978-07-01	62
1983-07-01	-25
1984-07-01	50
1986-07-01	-34
1992-07-01	-50
2002-01-01	450
2002-07-01	300
2003-10-01	200
2004-10-01	500
2005-01-01	-450
2005-04-01	500
2005-07-01	697
2005-10-01	68
2006-01-01	535
2006-04-01	-196
2006-07-01	-430
2006-10-01	222
2007-01-01	-9
2007-04-01	212
2007-07-01	-394
2007-10-01	-105
2008-01-01	359
2008-04-01	-39
2008-07-01	-9
2008-10-01	-301
2009-01-01	-23
2009-10-01	-500
2010-04-01	-500
2010-07-01	400
2011-01-01	177
2011-04-01	-576
2011-07-01	250
2011-10-01	-100
2012-04-01	92
2012-07-01	-131
2012-10-01	-57
2013-01-01	-195
2013-07-01	32
2014-07-01	717
2015-04-01	862
2015-10-01	-400
2016-01-01	-34
2016-04-01	582
2016-07-01	-185
2016-10-01	200
2017-01-01	5321
2017-04-01	1386
2017-07-01	131
2017-10-01	92
2018-01-01	12
2018-04-01	-23