Quarter	Millions of US Dollars
1999-04-01	159
1999-10-01	78
2001-10-01	181
2004-04-01	223
2008-01-01	605
2008-10-01	-263
2011-04-01	500
2012-01-01	1000
2012-10-01	1250
2014-01-01	2739
2014-04-01	823
2014-07-01	-1305
2014-10-01	19
2015-04-01	0
2015-07-01	556
2015-10-01	602
2016-01-01	0
2016-04-01	734
2016-10-01	1430
2017-01-01	-147
2017-04-01	1058
2018-01-01	-492
2018-04-01	1128