Quarter	Millions of US Dollars
1973-04-01	43
1978-04-01	25
1980-04-01	30
1982-04-01	40
1983-04-01	-25
1983-10-01	45
1984-10-01	-43
1985-04-01	30
1985-10-01	-19
1986-10-01	-16
1987-04-01	-32
1988-01-01	-18
1989-04-01	-60
1999-10-01	100
2001-07-01	1500
2004-10-01	-100
2005-07-01	2804
2006-01-01	378
2006-07-01	-500
2006-10-01	400
2007-01-01	750
2007-07-01	1055
2008-04-01	67
2009-04-01	138
2010-01-01	122
2010-04-01	883
2010-07-01	612
2010-10-01	47
2011-01-01	44
2011-04-01	-2141
2011-07-01	-988
2011-10-01	-1
2012-01-01	15
2012-04-01	-123
2012-07-01	-1002
2012-10-01	443
2013-01-01	10
2013-04-01	2736
2013-07-01	1041
2013-10-01	-383
2014-01-01	-62
2014-04-01	-17
2014-07-01	-4
2014-10-01	-2722
2015-01-01	-26
2015-04-01	1633
2015-07-01	-1861
2015-10-01	1046
2016-01-01	-13
2016-04-01	0
2016-07-01	-1542
2016-10-01	4161
2017-01-01	2082
2017-04-01	1597
2017-07-01	-11
2017-10-01	-1322
2018-01-01	2834
2018-04-01	4948