Quarter	Millions of US Dollars
2002-04-01	3006
2002-07-01	-2108
2002-10-01	-7888
2003-01-01	-601
2003-04-01	-5042
2003-07-01	987
2003-10-01	-2457
2004-01-01	2032
2004-04-01	3752
2004-07-01	-504
2004-10-01	3038
2005-01-01	8443
2005-04-01	9369
2005-07-01	7162
2005-10-01	11451
2006-01-01	7009
2006-04-01	10901
2006-07-01	6222
2006-10-01	12312
2007-01-01	5223
2007-04-01	5919
2007-07-01	18325
2007-10-01	8484
2008-01-01	29393
2008-04-01	52177
2008-07-01	55668
2008-10-01	19856
2009-01-01	4567
2009-04-01	7865
2009-07-01	-6068
2009-10-01	-1661
2010-01-01	8838
2010-04-01	12597
2010-07-01	26073
2010-10-01	38874
2011-01-01	53283
2011-04-01	45678
2011-07-01	35558
2011-10-01	28215
2012-01-01	9858
2012-04-01	8564
2012-07-01	10180
2012-10-01	-444
2013-01-01	9448
2013-04-01	16515
2013-07-01	11510
2013-10-01	18451
2014-01-01	21062
2014-04-01	32503
2014-07-01	13043
2014-10-01	17036
2015-01-01	11777
2015-04-01	10994
2015-07-01	10031
2015-10-01	22955
2016-01-01	9507
2016-04-01	11940
2016-07-01	5569
2016-10-01	2186
2017-01-01	-18186
2017-04-01	-7431
2017-07-01	-4739
2017-10-01	-13782
2018-01-01	-9371