Quarter	Millions of US Dollars
1976-07-01	367
1976-10-01	11
1981-10-01	-12
1987-07-01	-12
1988-01-01	-12
1988-07-01	-32
1989-01-01	-32
1989-07-01	-70
1992-01-01	-207
1993-07-01	100
1993-10-01	439
1994-04-01	405
1994-07-01	190
1994-10-01	115
1995-04-01	-7
1995-07-01	398
1995-10-01	114
1996-01-01	75
1996-04-01	446
1996-07-01	24
1996-10-01	635
1997-01-01	730
1997-04-01	248
1997-10-01	-29
1998-01-01	130
1998-04-01	296
1998-07-01	90
1998-10-01	-219
1999-04-01	171
1999-07-01	413
1999-10-01	-204
2000-01-01	300
2000-04-01	47
2000-07-01	-30
2000-10-01	-204
2001-01-01	-216
2001-04-01	-4
2001-07-01	37
2001-10-01	21
2002-01-01	-150
2002-04-01	1619
2002-07-01	-684
2002-10-01	-154
2003-01-01	66
2003-04-01	676
2003-07-01	-95
2003-10-01	1
2004-01-01	-29
2004-04-01	-140
2004-07-01	66
2004-10-01	-98
2005-01-01	6
2005-04-01	2
2005-07-01	256
2005-10-01	3
2006-01-01	306
2006-04-01	-172
2006-07-01	-246
2006-10-01	307
2007-01-01	-197
2007-04-01	-2
2007-07-01	7
2007-10-01	7
2008-01-01	179
2008-04-01	-292
2008-07-01	4
2008-10-01	5
2009-01-01	8
2009-04-01	834
2009-07-01	-91
2009-10-01	609
2010-01-01	-241
2010-04-01	-29
2010-07-01	-297
2010-10-01	758
2011-01-01	450
2011-04-01	875
2011-07-01	-400
2012-01-01	300
2012-04-01	-1
2013-01-01	440
2013-04-01	1850
2013-10-01	400
2014-04-01	-300
2014-07-01	-66
2015-04-01	-290
2015-07-01	125
2015-10-01	-99
2016-01-01	-300
2016-10-01	-619
2017-01-01	-528
2017-10-01	-693
2018-01-01	500
2018-04-01	-152