Quarter	Millions of US Dollars
2005-01-01	0
2005-04-01	0
2005-07-01	0
2005-10-01	0
2006-01-01	0
2006-04-01	0
2006-07-01	0
2006-10-01	14
2007-01-01	0
2007-04-01	0
2007-07-01	0
2007-10-01	0
2008-01-01	0
2008-04-01	0
2008-07-01	0
2008-10-01	-13
2009-01-01	0
2009-04-01	0
2009-07-01	0
2009-10-01	0
2010-01-01	0
2010-04-01	63
2010-07-01	49
2010-10-01	13
2011-01-01	0
2011-04-01	0
2011-07-01	0
2011-10-01	0
2012-01-01	56
2012-04-01	-14
2012-07-01	-11
2012-10-01	501
2013-01-01	436
2013-04-01	495
2013-07-01	351
2013-10-01	157
2014-01-01	82
2014-04-01	280
2014-07-01	503
2014-10-01	478
2015-01-01	130
2015-04-01	106
2015-07-01	10
2015-10-01	174
2016-01-01	128
2016-04-01	-169
2016-07-01	25
2016-10-01	-21
2017-01-01	198
2017-04-01	-460
2017-07-01	34
2017-10-01	-8
2018-01-01	166