Quarter	Millions of US Dollars
1975-04-01	53
1975-07-01	25
1978-07-01	25
1979-01-01	48
1979-04-01	35
1980-07-01	81
1980-10-01	29
1981-04-01	30
1982-07-01	-25
1985-07-01	-35
1985-10-01	-1
1986-01-01	-25
1986-07-01	-73
1986-10-01	-58
1990-04-01	-53
1991-01-01	245
1993-04-01	333
1993-10-01	100
1994-01-01	-96
1994-07-01	-15
1994-10-01	100
1996-01-01	430
1996-04-01	720
1996-07-01	440
1996-10-01	800
1997-01-01	750
1997-07-01	300
1997-10-01	650
1998-04-01	500
1998-10-01	413
1999-01-01	200
1999-04-01	1200
1999-07-01	286
2000-07-01	300
2001-04-01	605
2001-07-01	356
2001-10-01	650
2002-04-01	864
2002-07-01	371
2002-10-01	816
2003-01-01	928
2003-04-01	249
2003-07-01	860
2003-10-01	-263
2004-01-01	843
2004-07-01	-253
2004-10-01	1200
2005-01-01	-82
2005-04-01	150
2005-07-01	-61
2005-10-01	-200
2006-01-01	-657
2006-04-01	100
2006-07-01	-200
2006-10-01	200
2007-01-01	134
2007-07-01	-687
2007-10-01	-185
2008-01-01	-609
2008-04-01	-65
2008-07-01	-8
2009-01-01	591
2009-04-01	-1057
2009-07-01	851
2009-10-01	1451
2010-01-01	490
2010-04-01	880
2010-07-01	3418
2010-10-01	2557
2011-01-01	2145
2011-04-01	226
2011-07-01	1040
2011-10-01	1766
2012-01-01	300
2012-04-01	-132
2012-07-01	2970
2012-10-01	2694
2013-01-01	2109
2013-04-01	2098
2013-07-01	1711
2013-10-01	3633
2014-01-01	122
2014-04-01	1832
2014-07-01	5344
2014-10-01	4985
2015-01-01	870
2015-04-01	4543
2015-07-01	1842
2015-10-01	-484
2016-01-01	2007
2016-04-01	-821
2016-07-01	1006
2016-10-01	930
2017-01-01	311
2017-04-01	4030
2017-07-01	5841
2017-10-01	749
2018-01-01	2491
2018-04-01	763