Quarter	Millions of US Dollars
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	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	12
1981-01-01	12
1981-04-01	12
1981-07-01	12
1981-10-01	0
1982-01-01	0
1982-04-01	0
1982-07-01	0
1982-10-01	0
1983-01-01	25
1983-04-01	25
1983-07-01	25
1983-10-01	25
1984-01-01	0
1984-04-01	0
1984-07-01	0
1984-10-01	12
1985-01-01	40
1985-04-01	40
1985-07-01	41
1985-10-01	52
1986-01-01	25
1986-04-01	26
1986-07-01	39
1986-10-01	31
1987-01-01	44
1987-04-01	42
1987-07-01	62
1987-10-01	156
1988-01-01	175
1988-04-01	217
1988-07-01	289
1988-10-01	187
1989-01-01	151
1989-04-01	106
1989-07-01	0
1989-10-01	35
1990-01-01	63
1990-04-01	99
1990-07-01	241
1990-10-01	207
1991-01-01	524
1991-04-01	510
1991-07-01	377
1991-10-01	560
1992-01-01	395
1992-04-01	493
1992-07-01	590
1992-10-01	927
1993-01-01	983
1993-04-01	985
1993-07-01	1040
1993-10-01	710
1994-01-01	853
1994-04-01	1284
1994-07-01	1445
1994-10-01	1413
1995-01-01	662
1995-04-01	873
1995-07-01	1011
1995-10-01	1589
1996-01-01	2030
1996-04-01	2104
1996-07-01	2124
1996-10-01	2204
1997-01-01	2370
1997-04-01	2740
1997-07-01	3525
1997-10-01	3453
1998-01-01	3725
1998-04-01	4393
1998-07-01	4221
1998-10-01	5583
1999-01-01	5590
1999-04-01	5715
1999-07-01	5004
1999-10-01	4648
2000-01-01	5406
2000-04-01	5150
2000-07-01	5565
2000-10-01	5879
2001-01-01	5596
2001-04-01	5774
2001-07-01	6830
2001-10-01	6804
2002-01-01	6873
2002-04-01	7963
2002-07-01	7055
2002-10-01	7962
2003-01-01	8140
2003-04-01	9393
2003-07-01	9825
2003-10-01	9123
2004-01-01	9041
2004-04-01	7325
2004-07-01	7301
2004-10-01	6933
2005-01-01	8370
2005-04-01	9374
2005-07-01	9436
2005-10-01	10178
2006-01-01	10805
2006-04-01	11437
2006-07-01	13244
2006-10-01	12877
2007-01-01	13007
2007-04-01	12135
2007-07-01	10767
2007-10-01	11281
2008-01-01	10902
2008-04-01	10642
2008-07-01	9562
2008-10-01	7823
2009-01-01	7121
2009-04-01	6648
2009-07-01	7350
2009-10-01	8248
2010-01-01	9932
2010-04-01	12266
2010-07-01	12122
2010-10-01	13876
2011-01-01	13617
2011-04-01	14179
2011-07-01	15794
2011-10-01	17869
2012-01-01	18385
2012-04-01	17217
2012-07-01	15386
2012-10-01	12521
2013-01-01	10418
2013-04-01	15754
2013-07-01	19327
2013-10-01	22291
2014-01-01	23877
2014-04-01	18551
2014-07-01	16103
2014-10-01	16113
2015-01-01	16301
2015-04-01	18239
2015-07-01	17669
2015-10-01	18147
2016-01-01	18224
2016-04-01	22328
2016-07-01	23748
2016-10-01	20111
2017-01-01	20965
2017-04-01	18909
2017-07-01	18550
2017-10-01	19752
2018-01-01	22370
2018-04-01	24075