Quarter	Millions of US Dollars
1991-04-01	87
1994-10-01	10
1995-01-01	20
1995-07-01	5
1995-10-01	-10
1997-01-01	-20
1997-07-01	-5
1999-01-01	8
1999-04-01	53
1999-07-01	-23
1999-10-01	54
2000-01-01	-2
2000-04-01	90
2000-07-01	6
2000-10-01	554
2001-01-01	368
2001-04-01	1357
2001-07-01	1030
2001-10-01	404
2002-01-01	210
2002-04-01	579
2002-07-01	-1394
2002-10-01	354
2003-01-01	-145
2003-04-01	93
2003-07-01	242
2003-10-01	0
2004-01-01	220
2004-04-01	-31
2004-07-01	-718
2004-10-01	-549
2005-01-01	131
2005-04-01	38
2005-07-01	184
2005-10-01	12
2006-01-01	27
2006-04-01	-86
2006-07-01	-911
2006-10-01	-107
2007-01-01	-234
2007-04-01	199
2007-07-01	685
2007-10-01	-396
2008-01-01	-52
2008-04-01	-207
2008-07-01	-325
2008-10-01	-69
2009-01-01	-87
2009-04-01	-121
2009-07-01	-82
2009-10-01	-113
2010-01-01	-215
2010-04-01	-30
2010-07-01	-89
2010-10-01	-174
2011-01-01	-202
2011-04-01	-202
2011-07-01	-58
2011-10-01	-14
2012-01-01	-164
2012-04-01	-84
2012-07-01	0
2012-10-01	-29
2013-01-01	0
2013-04-01	-466
2013-07-01	0
2013-10-01	-4
2014-01-01	0
2014-04-01	1
2014-07-01	0
2014-10-01	-51
2015-01-01	-101
2015-04-01	-2
2015-07-01	-310
2015-10-01	0
2016-01-01	-12
2016-04-01	0
2016-07-01	0
2016-10-01	0
2017-01-01	-36
2017-04-01	0
2017-07-01	-131
2017-10-01	-76
2018-01-01	-4
2018-04-01	-64