Quarter	Millions of US Dollars
1975-10-01	18
1981-10-01	25
1986-10-01	-25
1987-10-01	-18
1990-10-01	50
1991-04-01	210
1991-10-01	33
1992-01-01	76
1992-07-01	64
1992-10-01	106
1993-01-01	30
1993-10-01	345
1994-01-01	-21
1994-04-01	464
1995-01-01	-550
1995-10-01	54
1996-01-01	175
1996-04-01	127
1996-07-01	71
1996-10-01	635
1997-01-01	489
1997-04-01	80
1997-07-01	-29
1997-10-01	-30
1998-01-01	-260
1998-04-01	516
1998-07-01	-62
1998-10-01	-162
1999-01-01	-71
1999-04-01	147
1999-07-01	-1305
1999-10-01	-250
2000-01-01	791
2000-04-01	-785
2000-10-01	-229
2001-01-01	-63
2001-04-01	-150
2002-01-01	-76
2002-04-01	-16
2003-04-01	-133
2003-07-01	42
2004-01-01	-100
2004-04-01	25
2004-10-01	38
2005-04-01	-20
2005-07-01	-1
2005-10-01	220
2006-04-01	-92
2006-10-01	-43
2007-04-01	700
2007-10-01	128
2008-04-01	-300
2008-07-01	-47
2008-10-01	-151
2009-07-01	375
2009-10-01	1415
2010-01-01	475
2010-04-01	250
2010-10-01	-50
2011-01-01	-435
2011-04-01	1500
2012-01-01	500
2012-04-01	2500
2012-10-01	850
2013-01-01	850
2013-04-01	1275
2014-04-01	2450
2014-07-01	-375
2014-10-01	-300
2015-01-01	-39
2015-04-01	1445
2016-01-01	-50
2017-01-01	0
2017-04-01	3225
2017-07-01	50
2017-10-01	696
2018-01-01	356
2018-04-01	3080