Quarter	Millions of US Dollars
1977-04-01	0
1977-07-01	0
1977-10-01	0
1978-01-01	0
1978-04-01	0
1978-07-01	0
1978-10-01	0
1979-01-01	0
1979-04-01	0
1979-07-01	0
1979-10-01	0
1980-01-01	0
1980-04-01	0
1980-07-01	0
1980-10-01	0
1981-01-01	0
1981-04-01	50
1981-07-01	50
1981-10-01	50
1982-01-01	50
1982-04-01	0
1982-07-01	0
1982-10-01	0
1983-01-01	0
1983-04-01	0
1983-07-01	0
1983-10-01	0
1984-01-01	0
1984-04-01	30
1984-07-01	30
1984-10-01	30
1985-01-01	30
1985-04-01	0
1985-07-01	0
1985-10-01	0
1986-01-01	0
1986-04-01	0
1986-07-01	0
1986-10-01	31
1987-01-01	33
1987-04-01	33
1987-07-01	33
1987-10-01	30
1988-01-01	30
1988-04-01	30
1988-07-01	70
1988-10-01	140
1989-01-01	140
1989-04-01	140
1989-07-01	103
1989-10-01	763
1990-01-01	1464
1990-04-01	1569
1990-07-01	1645
1990-10-01	959
1991-01-01	205
1991-04-01	181
1991-07-01	397
1991-10-01	399
1992-01-01	458
1992-04-01	754
1992-07-01	704
1992-10-01	579
1993-01-01	620
1993-04-01	409
1993-07-01	356
1993-10-01	385
1994-01-01	380
1994-04-01	389
1994-07-01	541
1994-10-01	483
1995-01-01	595
1995-04-01	499
1995-07-01	652
1995-10-01	1701
1996-01-01	985
1996-04-01	1142
1996-07-01	611
1996-10-01	400
1997-01-01	1393
1997-04-01	1480
1997-07-01	1563
1997-10-01	1403
1998-01-01	2021
1998-04-01	2502
1998-07-01	4355
1998-10-01	4370
1999-01-01	3226
1999-04-01	2682
1999-07-01	1268
1999-10-01	2547
2000-01-01	3750
2000-04-01	3386
2000-07-01	3443
2000-10-01	4287
2001-01-01	4068
2001-04-01	4900
2001-07-01	7403
2001-10-01	7691
2002-01-01	7710
2002-04-01	8455
2002-07-01	9755
2002-10-01	11614
2003-01-01	13549
2003-04-01	18771
2003-07-01	18623
2003-10-01	18474
2004-01-01	20109
2004-04-01	23164
2004-07-01	21020
2004-10-01	21930
2005-01-01	20564
2005-04-01	17411
2005-07-01	20912
2005-10-01	23520
2006-01-01	24244
2006-04-01	29371
2006-07-01	30940
2006-10-01	32632
2007-01-01	31375
2007-04-01	36474
2007-07-01	37103
2007-10-01	39789
2008-01-01	44837
2008-04-01	46174
2008-07-01	38608
2008-10-01	39109
2009-01-01	38663
2009-04-01	51365
2009-07-01	59157
2009-10-01	50055
2010-01-01	54519
2010-04-01	41427
2010-07-01	42937
2010-10-01	36799
2011-01-01	40783
2011-04-01	41698
2011-07-01	45497
2011-10-01	46166
2012-01-01	37516
2012-04-01	30804
2012-07-01	22901
2012-10-01	25305
2013-01-01	25689
2013-04-01	28084
2013-07-01	30592
2013-10-01	37110
2014-01-01	36080
2014-04-01	26064
2014-07-01	21922
2014-10-01	15432
2015-01-01	10077
2015-04-01	10412
2015-07-01	9078
2015-10-01	14643
2016-01-01	14900
2016-04-01	13716
2016-07-01	13522
2016-10-01	9645
2017-01-01	11025
2017-04-01	17343
2017-07-01	15582
2017-10-01	11072
2018-01-01	10521
2018-04-01	12002