Quarter	Millions of US Dollars
1975-01-01	60
1975-04-01	40
1983-01-01	-60
1983-04-01	-40
1996-01-01	50
1996-04-01	722
1996-10-01	272
1997-01-01	86
1997-04-01	352
1999-04-01	-655
2000-01-01	-88
2000-10-01	260
2001-01-01	92
2001-04-01	652
2001-10-01	-129
2002-04-01	341
2002-10-01	440
2003-07-01	814
2003-10-01	-178
2004-04-01	-181
2004-10-01	-46
2005-04-01	568
2005-10-01	-402
2006-04-01	-46
2006-10-01	-207
2007-04-01	-46
2007-10-01	-219
2008-04-01	229
2010-01-01	1429
2010-07-01	-903
2011-04-01	2158
2012-01-01	3255
2012-04-01	-897
2012-07-01	943
2012-10-01	1945
2013-01-01	1500
2013-07-01	1986
2013-10-01	1365
2014-01-01	2000
2014-04-01	1714
2014-10-01	1874
2015-01-01	-1125
2015-04-01	-552
2015-07-01	1995
2015-10-01	1277
2016-01-01	557
2016-04-01	516
2016-07-01	4
2016-10-01	2124
2017-01-01	1
2017-04-01	1948
2017-07-01	-20
2017-10-01	1762
2018-01-01	3149
2018-04-01	-1944