Quarter	Millions of US Dollars
1986-04-01	250
1996-04-01	-250
1998-07-01	82
1999-01-01	579
1999-04-01	1273
1999-10-01	532
2000-01-01	206
2000-10-01	335
2001-01-01	0
2001-04-01	862
2003-01-01	1081
2003-07-01	1044
2004-01-01	1239
2004-04-01	748
2004-07-01	786
2004-10-01	1363
2005-01-01	2788
2005-04-01	958
2005-07-01	686
2005-10-01	-706
2006-01-01	2520
2006-04-01	-750
2006-07-01	633
2006-10-01	-100
2007-01-01	1295
2007-10-01	214
2008-04-01	2667
2009-01-01	-651
2009-04-01	-514
2009-07-01	1685
2010-01-01	2000
2010-07-01	-1640
2011-01-01	3750
2011-04-01	504
2011-10-01	-1347
2012-07-01	-572
2012-10-01	-1297
2013-01-01	1388
2013-04-01	-159
2013-10-01	3219
2014-01-01	1630
2014-04-01	-841
2014-07-01	-2429
2015-01-01	-1500
2016-01-01	-715
2016-04-01	-51
2016-07-01	-1117
2017-04-01	-640
2017-07-01	-1174
2017-10-01	952
2018-01-01	-986
2018-04-01	-1786