Quarter	Millions of US Dollars
1975-01-01	60
1975-04-01	40
1983-01-01	-60
1983-04-01	-40
1996-01-01	50
1996-04-01	722
1996-10-01	272
1997-01-01	86
1997-04-01	552
1997-07-01	3
1997-10-01	3
1998-01-01	3
1998-04-01	3
1998-07-01	3
1998-10-01	4
1999-01-01	4
1999-04-01	-652
1999-07-01	4
1999-10-01	4
2000-01-01	-84
2000-04-01	4
2000-07-01	4
2000-10-01	263
2001-01-01	96
2001-04-01	656
2001-07-01	4
2001-10-01	-125
2002-01-01	4
2002-04-01	345
2002-07-01	4
2002-10-01	444
2003-01-01	5
2003-04-01	5
2003-07-01	818
2003-10-01	-173
2004-01-01	5
2004-04-01	-176
2004-07-01	5
2004-10-01	-41
2005-01-01	5
2005-04-01	573
2005-07-01	5
2005-10-01	256
2006-01-01	6
2006-04-01	-40
2006-07-01	6
2006-10-01	77
2007-01-01	6
2007-04-01	-420
2007-10-01	-219
2008-04-01	229
2008-10-01	-500
2009-10-01	48
2010-01-01	1446
2010-04-01	44
2010-07-01	-925
2010-10-01	44
2011-01-01	34
2011-04-01	2203
2011-07-01	38
2011-10-01	-211
2012-01-01	3434
2012-04-01	-895
2012-07-01	943
2012-10-01	1939
2013-01-01	1501
2013-04-01	-9
2013-07-01	1982
2013-10-01	1143
2014-01-01	1905
2014-04-01	1679
2014-07-01	0
2014-10-01	1854
2015-01-01	-1184
2015-04-01	-556
2015-07-01	1995
2015-10-01	851
2016-01-01	537
2016-04-01	516
2016-07-01	-8
2016-10-01	2124
2017-01-01	-7
2017-04-01	1333
2017-07-01	-20
2017-10-01	1173
2018-01-01	2473
2018-04-01	-1942