Quarter	Millions of US Dollars
1971-10-01	0
1972-01-01	0
1972-04-01	0
1972-07-01	0
1972-10-01	0
1973-01-01	0
1973-04-01	0
1973-07-01	0
1973-10-01	0
1974-01-01	0
1974-04-01	0
1974-07-01	0
1974-10-01	0
1975-01-01	0
1975-04-01	0
1975-07-01	0
1975-10-01	0
1976-01-01	0
1976-04-01	0
1976-07-01	0
1976-10-01	0
1977-01-01	0
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	19
1979-01-01	110
1979-04-01	111
1979-07-01	114
1979-10-01	110
1980-01-01	64
1980-04-01	127
1980-07-01	211
1980-10-01	188
1981-01-01	150
1981-04-01	356
1981-07-01	452
1981-10-01	561
1982-01-01	728
1982-04-01	528
1982-07-01	433
1982-10-01	538
1983-01-01	382
1983-04-01	357
1983-07-01	446
1983-10-01	302
1984-01-01	345
1984-04-01	296
1984-07-01	261
1984-10-01	557
1985-01-01	498
1985-04-01	635
1985-07-01	650
1985-10-01	651
1986-01-01	912
1986-04-01	910
1986-07-01	842
1986-10-01	757
1987-01-01	746
1987-04-01	899
1987-07-01	1431
1987-10-01	1577
1988-01-01	1490
1988-04-01	1262
1988-07-01	773
1988-10-01	514
1989-01-01	513
1989-04-01	489
1989-07-01	463
1989-10-01	544
1990-01-01	1334
1990-04-01	1245
1990-07-01	1195
1990-10-01	1177
1991-01-01	264
1991-04-01	634
1991-07-01	761
1991-10-01	779
1992-01-01	1170
1992-04-01	754
1992-07-01	1134
1992-10-01	1140
1993-01-01	680
1993-04-01	768
1993-07-01	3368
1993-10-01	3785
1994-01-01	5718
1994-04-01	6392
1994-07-01	7329
1994-10-01	5833
1995-01-01	3280
1995-04-01	5451
1995-07-01	7762
1995-10-01	8071
1996-01-01	7956
1996-04-01	5532
1996-07-01	9977
1996-10-01	10598
1997-01-01	10948
1997-04-01	12075
1997-07-01	6350
1997-10-01	5983
1998-01-01	5964
1998-04-01	4398
1998-07-01	3158
1998-10-01	3550
1999-01-01	3574
1999-04-01	5151
1999-07-01	5801
1999-10-01	7199
2000-01-01	6425
2000-04-01	11068
2000-07-01	10106
2000-10-01	14561
2001-01-01	14713
2001-04-01	13858
2001-07-01	15264
2001-10-01	8754
2002-01-01	18023
2002-04-01	20481
2002-07-01	21944
2002-10-01	23324
2003-01-01	14809
2003-04-01	12423
2003-07-01	10222
2003-10-01	11056
2004-01-01	9910
2004-04-01	7473
2004-07-01	5697
2004-10-01	4049
2005-01-01	5708
2005-04-01	5019
2005-07-01	6763
2005-10-01	7288
2006-01-01	7150
2006-04-01	6565
2006-07-01	5605
2006-10-01	5218
2007-01-01	5019
2007-04-01	5539
2007-07-01	5719
2007-10-01	8692
2008-01-01	11318
2008-04-01	10501
2008-07-01	10047
2008-10-01	7172
2009-01-01	7749
2009-04-01	7110
2009-07-01	6648
2009-10-01	7116
2010-01-01	5596
2010-04-01	5018
2010-07-01	5013
2010-10-01	2069
2011-01-01	2121
2011-04-01	4595
2011-07-01	4111
2011-10-01	4794
2012-01-01	3861
2012-04-01	4223
2012-07-01	8265
2012-10-01	9515
2013-01-01	12260
2013-04-01	13197
2013-07-01	11041
2013-10-01	10600
2014-01-01	13566
2014-04-01	13813
2014-07-01	13507
2014-10-01	12047
2015-01-01	6715
2015-04-01	4545
2015-07-01	12211
2015-10-01	15426
2016-01-01	16324
2016-04-01	22000
2016-07-01	14590
2016-10-01	16537
2017-01-01	15567
2017-04-01	12850
2017-07-01	14868
2017-10-01	9276
2018-01-01	8915
2018-04-01	12221