Quarter	Millions of US Dollars
1972-01-01	20
1972-04-01	20
1974-07-01	9
1976-10-01	14
1977-04-01	2
1977-07-01	25
1978-01-01	91
1978-07-01	70
1978-10-01	42
1979-01-01	81
1980-04-01	-20
1980-07-01	25
1982-01-01	-14
1982-07-01	-25
1983-01-01	-9
1984-01-01	-20
1985-10-01	-56
1986-01-01	-20
1986-10-01	-12
1987-01-01	-3
1987-07-01	-26
1988-01-01	-92
1990-07-01	-24
1993-01-01	-41
1994-01-01	-112
1996-01-01	2
1996-04-01	5
1996-07-01	3224
1996-10-01	-2
1997-01-01	493
1997-04-01	8
1997-07-01	815
1997-10-01	-7
1998-01-01	-1
1998-04-01	300
1998-07-01	0
1998-10-01	-614
1999-01-01	500
1999-07-01	-1
2000-04-01	-26
2000-07-01	350
2001-01-01	1031
2001-04-01	-145
2001-07-01	-43
2001-10-01	-354
2002-01-01	-347
2002-07-01	96
2002-10-01	29
2003-01-01	168
2003-04-01	-2
2003-07-01	-47
2004-01-01	179
2004-04-01	-24
2004-07-01	-9
2004-10-01	600
2005-07-01	400
2005-10-01	1111
2006-01-01	1003
2006-04-01	-610
2006-07-01	-46
2007-04-01	450
2007-10-01	320
2008-04-01	-330
2009-01-01	323
2009-10-01	1000
2010-10-01	-150
2011-01-01	79
2011-07-01	715
2012-01-01	-150
2012-07-01	-280
2012-10-01	1500
2013-04-01	750
2013-07-01	100
2013-10-01	330
2014-04-01	369
2014-07-01	1250
2014-10-01	180
2015-01-01	-96
2015-04-01	150
2015-10-01	450
2016-01-01	1000
2016-04-01	925
2016-10-01	550
2017-01-01	150
2017-04-01	1422
2017-07-01	1045
2017-10-01	-496
2018-01-01	4
2018-04-01	1246