Quarter	Millions of US Dollars
2002-01-01	-300
2002-04-01	889
2002-07-01	2224
2002-10-01	-3464
2003-01-01	-1579
2003-04-01	192
2003-07-01	-60
2003-10-01	-1998
2004-01-01	102
2004-04-01	1704
2004-07-01	501
2004-10-01	-909
2005-01-01	1356
2005-04-01	1946
2005-07-01	-72
2005-10-01	-2927
2006-01-01	1418
2006-04-01	529
2006-07-01	243
2006-10-01	-1962
2007-01-01	1795
2007-04-01	2327
2007-07-01	178
2007-10-01	2
2008-01-01	-566
2008-04-01	5850
2008-07-01	-378
2008-10-01	-3679
2009-01-01	729
2009-04-01	-58
2009-07-01	-961
2009-10-01	-3246
2010-01-01	-778
2010-04-01	1001
2010-07-01	-1591
2010-10-01	-885
2011-01-01	718
2011-04-01	1052
2011-07-01	900
2011-10-01	-1200
2012-01-01	864
2012-04-01	2310
2012-07-01	-1994
2012-10-01	1521
2013-01-01	-1789
2013-04-01	1016
2013-07-01	-838
2013-10-01	491
2014-01-01	1120
2014-04-01	1030
2014-07-01	-734
2014-10-01	-1455
2015-01-01	638
2015-04-01	2933
2015-07-01	232
2015-10-01	-1131
2016-01-01	1646
2016-04-01	423
2016-07-01	-316
2016-10-01	-567
2017-01-01	584
2017-04-01	953
2017-07-01	-506
2017-10-01	-795
2018-01-01	1247