Quarter	Millions of US Dollars
1968-07-01	0
1968-10-01	0
1969-01-01	0
1969-04-01	0
1969-07-01	0
1969-10-01	0
1970-01-01	0
1970-04-01	0
1970-07-01	0
1970-10-01	0
1971-01-01	0
1971-04-01	0
1971-07-01	0
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	40
1977-04-01	40
1977-07-01	40
1977-10-01	55
1978-01-01	16
1978-04-01	122
1978-07-01	499
1978-10-01	866
1979-01-01	1031
1979-04-01	1080
1979-07-01	787
1979-10-01	425
1980-01-01	288
1980-04-01	434
1980-07-01	671
1980-10-01	751
1981-01-01	765
1981-04-01	606
1981-07-01	413
1981-10-01	315
1982-01-01	281
1982-04-01	400
1982-07-01	446
1982-10-01	487
1983-01-01	947
1983-04-01	761
1983-07-01	785
1983-10-01	800
1984-01-01	406
1984-04-01	606
1984-07-01	1040
1984-10-01	2278
1985-01-01	3015
1985-04-01	3559
1985-07-01	3567
1985-10-01	3229
1986-01-01	2905
1986-04-01	2949
1986-07-01	3609
1986-10-01	4058
1987-01-01	4244
1987-04-01	4118
1987-07-01	3605
1987-10-01	2930
1988-01-01	3835
1988-04-01	3427
1988-07-01	5010
1988-10-01	5417
1989-01-01	4886
1989-04-01	6240
1989-07-01	5547
1989-10-01	6071
1990-01-01	6991
1990-04-01	6690
1990-07-01	6386
1990-10-01	8458
1991-01-01	9102
1991-04-01	9467
1991-07-01	11427
1991-10-01	10838
1992-01-01	10185
1992-04-01	11675
1992-07-01	12953
1992-10-01	13279
1993-01-01	16113
1993-04-01	16841
1993-07-01	23074
1993-10-01	22629
1994-01-01	21115
1994-04-01	20807
1994-07-01	20876
1994-10-01	18331
1995-01-01	19510
1995-04-01	21487
1995-07-01	21966
1995-10-01	21528
1996-01-01	21818
1996-04-01	22870
1996-07-01	23123
1996-10-01	26283
1997-01-01	26471
1997-04-01	28299
1997-07-01	28304
1997-10-01	31374
1998-01-01	33196
1998-04-01	35290
1998-07-01	41397
1998-10-01	46602
1999-01-01	50465
1999-04-01	54656
1999-07-01	64219
1999-10-01	71877
2000-01-01	74657
2000-04-01	82285
2000-07-01	80277
2000-10-01	91302
2001-01-01	86016
2001-04-01	89553
2001-07-01	91641
2001-10-01	94154
2002-01-01	91787
2002-04-01	98744
2002-07-01	118840
2002-10-01	130261
2003-01-01	151672
2003-04-01	150578
2003-07-01	149087
2003-10-01	165968
2004-01-01	156867
2004-04-01	166289
2004-07-01	163878
2004-10-01	175777
2005-01-01	174863
2005-04-01	165912
2005-07-01	155019
2005-10-01	166745
2006-01-01	166361
2006-04-01	179891
2006-07-01	178769
2006-10-01	186454
2007-01-01	210111
2007-04-01	226292
2007-07-01	226452
2007-10-01	258071
2008-01-01	286435
2008-04-01	299845
2008-07-01	298456
2008-10-01	274110
2009-01-01	264915
2009-04-01	274972
2009-07-01	281193
2009-10-01	266315
2010-01-01	272389
2010-04-01	242913
2010-07-01	289664
2010-10-01	283889
2011-01-01	330469
2011-04-01	337190
2011-07-01	331276
2011-10-01	336080
2012-01-01	340557
2012-04-01	316139
2012-07-01	321483
2012-10-01	342449
2013-01-01	352816
2013-04-01	384521
2013-07-01	377469
2013-10-01	346524
2014-01-01	348336
2014-04-01	327701
2014-07-01	317666
2014-10-01	309044
2015-01-01	281705
2015-04-01	298944
2015-07-01	308315
2015-10-01	287704
2016-01-01	329013
2016-04-01	309592
2016-07-01	297155
2016-10-01	265839
2017-01-01	269648
2017-04-01	293846
2017-07-01	315123
2017-10-01	316811
2018-01-01	352193
2018-04-01	321632