Quarter	Millions of US Dollars
1985-01-01	19
1986-07-01	26
1988-04-01	40
1990-01-01	-34
1991-07-01	-32
1994-04-01	14
1994-07-01	0
1994-10-01	30
1995-10-01	124
1996-01-01	199
1996-04-01	-114
1996-07-01	19
1996-10-01	-79
1997-01-01	-123
1997-04-01	130
1997-07-01	-109
1997-10-01	-44
1998-04-01	-37
1999-10-01	-30
2000-04-01	100
2001-10-01	150
2005-01-01	200
2005-10-01	125
2006-04-01	150
2006-10-01	65
2008-01-01	323
2009-10-01	450
2010-01-01	-200
2010-04-01	90
2010-07-01	200
2011-07-01	-161
2014-04-01	-450
2014-10-01	-190
2015-07-01	320
2016-04-01	-150