Quarter	Millions of US Dollars
1976-01-01	17
1976-04-01	20
1978-04-01	30
1980-04-01	25
1981-01-01	-18
1983-04-01	-22
1985-04-01	-30
1985-10-01	-8
1986-10-01	-8
1987-04-01	-9
1996-04-01	220
1996-07-01	325
1996-10-01	-135
1997-04-01	233
1997-10-01	-4
1998-04-01	552
1998-10-01	-4
1999-01-01	439
1999-04-01	-4
1999-10-01	-4
2000-01-01	385
2000-04-01	-4
2000-10-01	-4
2001-01-01	92
2001-04-01	394
2001-07-01	-325
2001-10-01	6
2002-04-01	-15
2002-10-01	26
2003-01-01	9
2003-04-01	-4
2003-10-01	-6
2004-01-01	-7
2004-04-01	-250
2004-10-01	62
2005-04-01	-633
2005-10-01	-4
2006-01-01	16
2006-04-01	-4
2006-10-01	-8
2007-01-01	1452
2007-10-01	142
2008-01-01	1471
2009-01-01	-521
2009-07-01	2605
2009-10-01	634
2010-01-01	-691
2010-04-01	1255
2010-10-01	70
2011-01-01	486
2011-04-01	-647
2012-07-01	-2499
2012-10-01	2250
2013-01-01	262
2013-04-01	3500
2013-07-01	-117
2014-01-01	3500
2014-04-01	3245
2014-07-01	409
2014-10-01	-62
2015-04-01	-1436
2015-07-01	329
2016-01-01	-84
2016-04-01	56
2016-10-01	-624
2017-07-01	-352
2017-10-01	-1177
2018-01-01	-1229
2018-04-01	-1000