Quarter	Millions of US Dollars
1971-01-01	15
1971-04-01	15
1971-07-01	15
1971-10-01	63
1972-01-01	143
1972-04-01	175
1972-07-01	294
1972-10-01	361
1973-01-01	450
1973-04-01	498
1973-07-01	564
1973-10-01	532
1974-01-01	581
1974-04-01	582
1974-07-01	578
1974-10-01	672
1975-01-01	826
1975-04-01	854
1975-07-01	950
1975-10-01	1048
1976-01-01	1126
1976-04-01	1161
1976-07-01	1248
1976-10-01	1443
1977-01-01	1485
1977-04-01	1583
1977-07-01	1682
1977-10-01	1991
1978-01-01	2398
1978-04-01	2700
1978-07-01	3059
1978-10-01	3316
1979-01-01	3508
1979-04-01	3657
1979-07-01	3801
1979-10-01	3926
1980-01-01	3646
1980-04-01	4007
1980-07-01	3950
1980-10-01	3814
1981-01-01	3666
1981-04-01	3688
1981-07-01	3738
1981-10-01	4084
1982-01-01	3954
1982-04-01	3987
1982-07-01	4081
1982-10-01	4445
1983-01-01	4480
1983-04-01	4637
1983-07-01	4725
1983-10-01	4646
1984-01-01	4933
1984-04-01	5004
1984-07-01	5008
1984-10-01	5036
1985-01-01	5352
1985-04-01	5516
1985-07-01	5964
1985-10-01	6079
1986-01-01	6759
1986-04-01	7532
1986-07-01	8265
1986-10-01	8463
1987-01-01	10747
1987-04-01	11351
1987-07-01	12082
1987-10-01	13806
1988-01-01	14254
1988-04-01	14650
1988-07-01	15378
1988-10-01	15686
1989-01-01	16729
1989-04-01	16332
1989-07-01	17365
1989-10-01	17492
1990-01-01	18386
1990-04-01	20797
1990-07-01	23339
1990-10-01	24787
1991-01-01	25571
1991-04-01	25110
1991-07-01	27367
1991-10-01	29838
1992-01-01	30263
1992-04-01	35852
1992-07-01	38904
1992-10-01	39626
1993-01-01	42808
1993-04-01	45147
1993-07-01	43140
1993-10-01	40645
1994-01-01	43429
1994-04-01	46638
1994-07-01	51376
1994-10-01	51037
1995-01-01	55638
1995-04-01	55162
1995-07-01	52635
1995-10-01	50669
1996-01-01	51861
1996-04-01	50373
1996-07-01	49231
1996-10-01	49709
1997-01-01	48952
1997-04-01	48694
1997-07-01	46249
1997-10-01	44002
1998-01-01	40800
1998-04-01	40908
1998-07-01	42552
1998-10-01	41690
1999-01-01	38419
1999-04-01	37571
1999-07-01	40594
1999-10-01	39536
2000-01-01	36513
2000-04-01	37009
2000-07-01	34677
2000-10-01	34294
2001-01-01	32141
2001-04-01	36488
2001-07-01	37166
2001-10-01	35895
2002-01-01	37245
2002-04-01	39872
2002-07-01	38367
2002-10-01	40926
2003-01-01	49193
2003-04-01	55069
2003-07-01	58569
2003-10-01	60368
2004-01-01	62509
2004-04-01	63620
2004-07-01	62709
2004-10-01	69281
2005-01-01	68354
2005-04-01	64503
2005-07-01	64486
2005-10-01	64334
2006-01-01	69864
2006-04-01	75429
2006-07-01	67232
2006-10-01	69952
2007-01-01	68639
2007-04-01	70624
2007-07-01	67100
2007-10-01	66450
2008-01-01	68206
2008-04-01	68940
2008-07-01	59002
2008-10-01	59972
2009-01-01	64059
2009-04-01	70991
2009-07-01	75511
2009-10-01	77155
2010-01-01	76998
2010-04-01	73338
2010-07-01	81498
2010-10-01	85176
2011-01-01	103152
2011-04-01	104147
2011-07-01	98554
2011-10-01	96394
2012-01-01	106407
2012-04-01	108851
2012-07-01	110824
2012-10-01	115126
2013-01-01	116768
2013-04-01	121022
2013-07-01	128911
2013-10-01	133769
2014-01-01	137605
2014-04-01	144997
2014-07-01	139996
2014-10-01	136622
2015-01-01	129500
2015-04-01	138854
2015-07-01	143109
2015-10-01	139632
2016-01-01	141311
2016-04-01	144266
2016-07-01	146980
2016-10-01	144366
2017-01-01	149547
2017-04-01	156061
2017-07-01	165150
2017-10-01	170659
2018-01-01	179359
2018-04-01	170233