Quarter	Millions of US Dollars
1979-01-01	48
1980-07-01	56
1986-07-01	-48
1991-01-01	245
1996-01-01	-320
1999-04-01	500
2001-10-01	650
2002-04-01	864
2002-10-01	100
2003-01-01	1000
2004-01-01	600
2005-07-01	-366
2007-07-01	-600
2008-01-01	-600
2009-04-01	-500
2010-07-01	1524
2011-07-01	1352
2012-01-01	-750
2012-10-01	1500
2013-01-01	-1000
2014-07-01	50
2014-10-01	2055
2015-04-01	1584
2016-01-01	2658
2016-04-01	-50
2017-04-01	2326
2018-01-01	3025