Quarter	Millions of US Dollars
1997-04-01	352
2000-10-01	260
2001-01-01	142
2001-04-01	517
2002-04-01	341
2003-07-01	814
2003-10-01	-178
2005-04-01	614
2005-10-01	-356
2008-04-01	229
2010-01-01	1429
2010-07-01	-903
2011-04-01	2158
2012-01-01	3255
2012-04-01	-897
2012-07-01	943
2012-10-01	1945
2013-01-01	1500
2013-07-01	1986
2013-10-01	1365
2014-01-01	2000
2014-04-01	1714
2014-10-01	1874
2015-01-01	-1125
2015-04-01	-552
2015-07-01	1995
2015-10-01	851
2016-01-01	557
2016-04-01	516
2016-07-01	4
2016-10-01	2124
2017-01-01	1
2017-04-01	1332
2017-07-01	-20
2017-10-01	1173
2018-01-01	2473
2018-04-01	-1944