Quarter	Millions of US Dollars
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	48
1978-10-01	105
1979-01-01	218
1979-04-01	229
1979-07-01	200
1979-10-01	169
1980-01-01	41
1980-04-01	37
1980-07-01	67
1980-10-01	62
1981-01-01	179
1981-04-01	253
1981-07-01	277
1981-10-01	270
1982-01-01	214
1982-04-01	123
1982-07-01	71
1982-10-01	76
1983-01-01	48
1983-04-01	137
1983-07-01	201
1983-10-01	330
1984-01-01	447
1984-04-01	333
1984-07-01	251
1984-10-01	386
1985-01-01	299
1985-04-01	330
1985-07-01	550
1985-10-01	436
1986-01-01	568
1986-04-01	652
1986-07-01	550
1986-10-01	366
1987-01-01	386
1987-04-01	376
1987-07-01	464
1987-10-01	665
1988-01-01	662
1988-04-01	746
1988-07-01	668
1988-10-01	682
1989-01-01	649
1989-04-01	439
1989-07-01	453
1989-10-01	638
1990-01-01	419
1990-04-01	395
1990-07-01	516
1990-10-01	249
1991-01-01	565
1991-04-01	618
1991-07-01	752
1991-10-01	1011
1992-01-01	1264
1992-04-01	1697
1992-07-01	2085
1992-10-01	1927
1993-01-01	2283
1993-04-01	1972
1993-07-01	1628
1993-10-01	1401
1994-01-01	586
1994-04-01	1476
1994-07-01	1813
1994-10-01	1823
1995-01-01	2204
1995-04-01	1918
1995-07-01	1706
1995-10-01	2069
1996-01-01	3026
1996-04-01	2165
1996-07-01	2056
1996-10-01	2434
1997-01-01	2897
1997-04-01	3101
1997-07-01	2817
1997-10-01	2189
1998-01-01	1088
1998-04-01	1904
1998-07-01	5281
1998-10-01	7426
1999-01-01	7314
1999-04-01	7154
1999-07-01	4793
1999-10-01	3772
2000-01-01	7275
2000-04-01	6797
2000-07-01	6327
2000-10-01	3688
2001-01-01	5869
2001-04-01	5092
2001-07-01	4247
2001-10-01	3441
2002-01-01	5313
2002-04-01	5841
2002-07-01	4374
2002-10-01	3420
2003-01-01	5587
2003-04-01	5550
2003-07-01	4460
2003-10-01	5017
2004-01-01	6656
2004-04-01	7459
2004-07-01	8346
2004-10-01	8133
2005-01-01	15262
2005-04-01	16079
2005-07-01	13502
2005-10-01	9448
2006-01-01	10100
2006-04-01	11369
2006-07-01	8645
2006-10-01	6468
2007-01-01	13776
2007-04-01	22180
2007-07-01	25527
2007-10-01	3298
2008-01-01	9562
2008-04-01	8429
2008-07-01	7974
2008-10-01	15674
2009-01-01	20966
2009-04-01	18000
2009-07-01	12301
2009-10-01	10693
2010-01-01	14703
2010-04-01	14497
2010-07-01	13209
2010-10-01	11524
2011-01-01	18448
2011-04-01	13271
2011-07-01	17579
2011-10-01	15232
2012-01-01	11818
2012-04-01	15590
2012-07-01	10750
2012-10-01	15565
2013-01-01	19038
2013-04-01	11640
2013-07-01	21757
2013-10-01	19712
2014-01-01	17732
2014-04-01	15457
2014-07-01	16149
2014-10-01	13387
2015-01-01	12758
2015-04-01	14765
2015-07-01	15356
2015-10-01	13780
2016-01-01	18178
2016-04-01	15103
2016-07-01	16054
2016-10-01	16342
2017-01-01	19190
2017-04-01	17753
2017-07-01	11905
2017-10-01	14154
2018-01-01	16640
2018-04-01	17901