Quarter	Millions of US Dollars
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	32
1976-07-01	33
1976-10-01	33
1977-01-01	31
1977-04-01	0
1977-07-01	0
1977-10-01	37
1978-01-01	40
1978-04-01	40
1978-07-01	48
1978-10-01	8
1979-01-01	9
1979-04-01	49
1979-07-01	188
1979-10-01	240
1980-01-01	355
1980-04-01	407
1980-07-01	273
1980-10-01	284
1981-01-01	202
1981-04-01	339
1981-07-01	349
1981-10-01	356
1982-01-01	665
1982-04-01	748
1982-07-01	1289
1982-10-01	1292
1983-01-01	1086
1983-04-01	1106
1983-07-01	588
1983-10-01	550
1984-01-01	651
1984-04-01	412
1984-07-01	593
1984-10-01	1387
1985-01-01	1263
1985-04-01	1321
1985-07-01	1268
1985-10-01	842
1986-01-01	1201
1986-04-01	2477
1986-07-01	3092
1986-10-01	2935
1987-01-01	3217
1987-04-01	2234
1987-07-01	1870
1987-10-01	2842
1988-01-01	3143
1988-04-01	3733
1988-07-01	4108
1988-10-01	4101
1989-01-01	3957
1989-04-01	3202
1989-07-01	2723
1989-10-01	2364
1990-01-01	2469
1990-04-01	2918
1990-07-01	3485
1990-10-01	5714
1991-01-01	5259
1991-04-01	5731
1991-07-01	6265
1991-10-01	4122
1992-01-01	3827
1992-04-01	3901
1992-07-01	3878
1992-10-01	4732
1993-01-01	5062
1993-04-01	4403
1993-07-01	4117
1993-10-01	3303
1994-01-01	3119
1994-04-01	2638
1994-07-01	1856
1994-10-01	2338
1995-01-01	3981
1995-04-01	6769
1995-07-01	9405
1995-10-01	10620
1996-01-01	9209
1996-04-01	7332
1996-07-01	7604
1996-10-01	9243
1997-01-01	8727
1997-04-01	9647
1997-07-01	8731
1997-10-01	7588
1998-01-01	10658
1998-04-01	9687
1998-07-01	11143
1998-10-01	9425
1999-01-01	9106
1999-04-01	12493
1999-07-01	10809
1999-10-01	11458
2000-01-01	10205
2000-04-01	10095
2000-07-01	9341
2000-10-01	9995
2001-01-01	9280
2001-04-01	8631
2001-07-01	10971
2001-10-01	9478
2002-01-01	15424
2002-04-01	14540
2002-07-01	11820
2002-10-01	14044
2003-01-01	7578
2003-04-01	9166
2003-07-01	9752
2003-10-01	10001
2004-01-01	9234
2004-04-01	5920
2004-07-01	8719
2004-10-01	7685
2005-01-01	12094
2005-04-01	13491
2005-07-01	10770
2005-10-01	11847
2006-01-01	7860
2006-04-01	7756
2006-07-01	9904
2006-10-01	9132
2007-01-01	10344
2007-04-01	10989
2007-07-01	12186
2007-10-01	15611
2008-01-01	16536
2008-04-01	17160
2008-07-01	15535
2008-10-01	10866
2009-01-01	9307
2009-04-01	8290
2009-07-01	7268
2009-10-01	6500
2010-01-01	6623
2010-04-01	9182
2010-07-01	7527
2010-10-01	9188
2011-01-01	10326
2011-04-01	10467
2011-07-01	10478
2011-10-01	12442
2012-01-01	11880
2012-04-01	14759
2012-07-01	15550
2012-10-01	12922
2013-01-01	12773
2013-04-01	14096
2013-07-01	16123
2013-10-01	15595
2014-01-01	17965
2014-04-01	24779
2014-07-01	23545
2014-10-01	22898
2015-01-01	19776
2015-04-01	17181
2015-07-01	19183
2015-10-01	21969
2016-01-01	23854
2016-04-01	19284
2016-07-01	13664
2016-10-01	13537
2017-01-01	13367
2017-04-01	13258
2017-07-01	16858
2017-10-01	14137
2018-01-01	17130
2018-04-01	20023