Quarter	Millions of US Dollars
2007-01-01	61
2007-04-01	57
2007-07-01	-27
2007-10-01	229
2008-01-01	92
2008-04-01	-130
2008-07-01	62
2008-10-01	17
2009-01-01	-31
2009-04-01	-37
2009-07-01	-24
2009-10-01	12
2010-01-01	-28
2010-04-01	0
2010-07-01	2
2010-10-01	-220
2011-01-01	-51
2011-04-01	-50
2011-07-01	52
2011-10-01	35
2012-01-01	-6
2012-04-01	15
2012-07-01	-43
2012-10-01	-10
2013-01-01	-5
2013-04-01	-2
2013-07-01	18
2013-10-01	-110
2014-01-01	-16
2014-04-01	-48
2014-07-01	-5
2014-10-01	29
2015-01-01	-2
2015-04-01	-68
2015-07-01	55
2015-10-01	31
2016-01-01	1
2016-04-01	17
2016-07-01	242
2016-10-01	6
2017-01-01	4
2017-04-01	-18
2017-07-01	54
2017-10-01	-13
2018-01-01	15