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	0
1977-04-01	0
1977-07-01	0
1977-10-01	0
1978-01-01	0
1978-04-01	36
1978-07-01	287
1978-10-01	470
1979-01-01	521
1979-04-01	564
1979-07-01	375
1979-10-01	206
1980-01-01	176
1980-04-01	271
1980-07-01	369
1980-10-01	408
1981-01-01	405
1981-04-01	305
1981-07-01	200
1981-10-01	141
1982-01-01	82
1982-04-01	160
1982-07-01	162
1982-10-01	183
1983-01-01	468
1983-04-01	332
1983-07-01	367
1983-10-01	388
1984-01-01	163
1984-04-01	254
1984-07-01	277
1984-10-01	446
1985-01-01	589
1985-04-01	511
1985-07-01	616
1985-10-01	510
1986-01-01	337
1986-04-01	394
1986-07-01	580
1986-10-01	875
1987-01-01	1228
1987-04-01	1298
1987-07-01	1092
1987-10-01	765
1988-01-01	592
1988-04-01	479
1988-07-01	373
1988-10-01	339
1989-01-01	265
1989-04-01	311
1989-07-01	732
1989-10-01	891
1990-01-01	1128
1990-04-01	1213
1990-07-01	910
1990-10-01	1466
1991-01-01	1682
1991-04-01	1963
1991-07-01	2008
1991-10-01	1643
1992-01-01	1352
1992-04-01	1264
1992-07-01	2177
1992-10-01	1860
1993-01-01	2064
1993-04-01	1759
1993-07-01	2835
1993-10-01	3060
1994-01-01	2803
1994-04-01	3479
1994-07-01	3529
1994-10-01	3019
1995-01-01	3286
1995-04-01	3763
1995-07-01	3671
1995-10-01	3205
1996-01-01	3120
1996-04-01	2439
1996-07-01	2162
1996-10-01	2913
1997-01-01	2430
1997-04-01	2436
1997-07-01	2489
1997-10-01	2341
1998-01-01	1958
1998-04-01	2565
1998-07-01	2408
1998-10-01	3342
1999-01-01	3171
1999-04-01	4308
1999-07-01	6939
1999-10-01	8547
2000-01-01	9240
2000-04-01	10742
2000-07-01	11395
2000-10-01	17660
2001-01-01	18829
2001-04-01	13887
2001-07-01	14648
2001-10-01	15544
2002-01-01	14520
2002-04-01	13700
2002-07-01	16114
2002-10-01	16019
2003-01-01	15023
2003-04-01	18751
2003-07-01	17871
2003-10-01	23647
2004-01-01	21866
2004-04-01	20659
2004-07-01	18246
2004-10-01	20127
2005-01-01	18406
2005-04-01	19669
2005-07-01	16470
2005-10-01	16915
2006-01-01	15860
2006-04-01	15626
2006-07-01	14484
2006-10-01	18012
2007-01-01	16327
2007-04-01	20649
2007-07-01	14149
2007-10-01	15921
2008-01-01	17082
2008-04-01	13526
2008-07-01	13989
2008-10-01	13143
2009-01-01	13273
2009-04-01	11532
2009-07-01	12366
2009-10-01	10845
2010-01-01	12574
2010-04-01	12301
2010-07-01	10895
2010-10-01	13140
2011-01-01	10215
2011-04-01	9404
2011-07-01	7208
2011-10-01	10753
2012-01-01	16049
2012-04-01	17335
2012-07-01	21206
2012-10-01	22894
2013-01-01	24914
2013-04-01	25871
2013-07-01	20858
2013-10-01	17653
2014-01-01	20241
2014-04-01	22825
2014-07-01	19628
2014-10-01	18639
2015-01-01	16546
2015-04-01	14775
2015-07-01	14018
2015-10-01	15142
2016-01-01	21688
2016-04-01	22489
2016-07-01	23081
2016-10-01	18818
2017-01-01	21398
2017-04-01	22357
2017-07-01	25085
2017-10-01	26171
2018-01-01	28451
2018-04-01	26590