Quarter	Millions of US Dollars
2007-01-01	1
2007-04-01	-4
2007-07-01	-15
2007-10-01	-4
2008-01-01	-3
2008-04-01	-3
2008-07-01	-7
2008-10-01	-2
2009-01-01	-1
2009-04-01	-16
2009-07-01	5
2009-10-01	11
2010-01-01	0
2010-04-01	2
2010-07-01	31
2010-10-01	1
2011-01-01	-22
2011-04-01	3
2011-07-01	134
2011-10-01	34
2012-01-01	-7
2012-04-01	4
2012-07-01	-12
2012-10-01	44
2013-01-01	3
2013-04-01	-2
2013-07-01	-2
2013-10-01	12
2014-01-01	1
2014-04-01	0
2014-07-01	-3
2014-10-01	11
2015-01-01	1
2015-04-01	-14
2015-07-01	-2
2015-10-01	12
2016-01-01	0
2016-04-01	0
2016-07-01	-3
2016-10-01	2
2017-01-01	0
2017-04-01	1
2017-07-01	-98
2017-10-01	12
2018-01-01	-10