Quarter	Millions of US Dollars
1973-01-01	20
1985-10-01	-16
1986-07-01	39
1986-10-01	-2
1987-04-01	49
1987-07-01	-1
1988-01-01	-1
1991-04-01	200
1992-04-01	-50
1993-04-01	125
1994-01-01	343
1994-07-01	-61
1995-07-01	143
1995-10-01	253
1996-01-01	485
1996-04-01	400
1996-07-01	0
1996-10-01	305
1997-01-01	1000
1998-01-01	388
1998-04-01	525
1998-07-01	650
1999-01-01	414
1999-04-01	500
1999-10-01	500
2000-01-01	750
2000-04-01	257
2000-07-01	271
2000-10-01	144
2001-01-01	784
2001-04-01	1608
2001-07-01	325
2001-10-01	874
2002-01-01	-216
2002-04-01	-719
2002-07-01	399
2002-10-01	500
2003-01-01	99
2003-04-01	-564
2003-07-01	400
2004-01-01	-172
2004-07-01	500
2004-10-01	374
2005-01-01	447
2005-04-01	149
2005-07-01	179
2005-10-01	130
2006-01-01	-245
2006-04-01	-526
2006-07-01	2115
2006-10-01	368
2007-01-01	-498
2007-04-01	732
2007-07-01	301
2008-01-01	-395
2008-04-01	-239
2009-01-01	1000
2009-04-01	115
2009-10-01	1503
2010-01-01	-641
2010-04-01	581
2010-07-01	215
2011-04-01	-872
2011-07-01	2000
2011-10-01	-129
2012-01-01	376
2012-07-01	549
2012-10-01	-278
2013-01-01	-85
2013-07-01	1600
2014-01-01	2000
2014-10-01	0
2015-01-01	2500
2015-07-01	1500
2015-10-01	-1020
2016-01-01	1427
2016-10-01	-125
2017-01-01	850
2017-07-01	1400