Quarter	Millions of US Dollars
1977-04-01	10
1979-04-01	15
1982-04-01	-10
1984-10-01	200
1986-04-01	-13
1987-10-01	-200
2003-10-01	270
2004-10-01	187
2005-10-01	700
2006-04-01	1000
2006-07-01	485
2006-10-01	1461
2007-01-01	600
2007-04-01	650
2007-07-01	2675
2008-04-01	1330
2008-07-01	-47
2008-10-01	-43
2009-01-01	82
2009-07-01	1877
2009-10-01	-10
2010-01-01	693
2010-10-01	300
2011-04-01	-1000
2011-07-01	150
2011-10-01	900
2012-01-01	-50
2012-04-01	1850
2012-07-01	-1000
2013-01-01	-1330
2013-04-01	2459
2013-07-01	1
2013-10-01	1275
2014-01-01	10
2014-04-01	2034
2014-07-01	-167
2014-10-01	32
2015-01-01	-1293
2015-04-01	-5
2015-07-01	-1494
2015-10-01	-945
2016-01-01	-19
2016-04-01	790
2016-07-01	813
2016-10-01	30236
2017-01-01	494
2017-04-01	10114
2017-07-01	203
2017-10-01	14454
2018-01-01	1456
2018-04-01	11084