Quarter	Millions of US Dollars
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	5
1979-01-01	40
1979-04-01	40
1979-07-01	40
1979-10-01	35
1980-01-01	0
1980-04-01	50
1980-07-01	50
1980-10-01	90
1981-01-01	138
1981-04-01	167
1981-07-01	218
1981-10-01	179
1982-01-01	135
1982-04-01	78
1982-07-01	27
1982-10-01	104
1983-01-01	102
1983-04-01	184
1983-07-01	239
1983-10-01	258
1984-01-01	268
1984-04-01	151
1984-07-01	91
1984-10-01	403
1985-01-01	465
1985-04-01	566
1985-07-01	641
1985-10-01	330
1986-01-01	385
1986-04-01	293
1986-07-01	556
1986-10-01	644
1987-01-01	556
1987-04-01	830
1987-07-01	862
1987-10-01	817
1988-01-01	1008
1988-04-01	657
1988-07-01	464
1988-10-01	613
1989-01-01	463
1989-04-01	404
1989-07-01	299
1989-10-01	109
1990-01-01	25
1990-04-01	71
1990-07-01	81
1990-10-01	83
1991-01-01	150
1991-04-01	80
1991-07-01	275
1991-10-01	610
1992-01-01	788
1992-04-01	900
1992-07-01	930
1992-10-01	789
1993-01-01	754
1993-04-01	919
1993-07-01	1461
1993-10-01	2172
1994-01-01	2440
1994-04-01	3422
1994-07-01	3402
1994-10-01	3972
1995-01-01	3372
1995-04-01	3045
1995-07-01	3967
1995-10-01	5320
1996-01-01	6566
1996-04-01	8581
1996-07-01	8518
1996-10-01	9763
1997-01-01	9073
1997-04-01	8422
1997-07-01	9126
1997-10-01	15285
1998-01-01	18511
1998-04-01	19009
1998-07-01	16333
1998-10-01	6540
1999-01-01	3756
1999-04-01	8416
1999-07-01	10428
1999-10-01	10147
2000-01-01	10897
2000-04-01	15651
2000-07-01	16522
2000-10-01	17705
2001-01-01	17850
2001-04-01	10217
2001-07-01	8286
2001-10-01	8293
2002-01-01	7160
2002-04-01	6812
2002-07-01	7734
2002-10-01	6997
2003-01-01	8698
2003-04-01	12399
2003-07-01	12587
2003-10-01	13690
2004-01-01	13835
2004-04-01	11520
2004-07-01	17441
2004-10-01	17623
2005-01-01	19413
2005-04-01	29033
2005-07-01	20330
2005-10-01	18873
2006-01-01	17314
2006-04-01	6864
2006-07-01	9493
2006-10-01	9142
2007-01-01	8693
2007-04-01	11064
2007-07-01	8658
2007-10-01	9190
2008-01-01	8854
2008-04-01	7494
2008-07-01	5629
2008-10-01	5213
2009-01-01	6630
2009-04-01	6697
2009-07-01	8265
2009-10-01	8123
2010-01-01	8848
2010-04-01	7370
2010-07-01	8843
2010-10-01	7384
2011-01-01	6285
2011-04-01	5950
2011-07-01	5045
2011-10-01	5451
2012-01-01	5939
2012-04-01	6831
2012-07-01	7823
2012-10-01	11856
2013-01-01	14185
2013-04-01	15720
2013-07-01	14946
2013-10-01	15960
2014-01-01	18559
2014-04-01	15752
2014-07-01	19789
2014-10-01	16402
2015-01-01	14309
2015-04-01	16474
2015-07-01	13029
2015-10-01	12225
2016-01-01	12248
2016-04-01	10934
2016-07-01	9698
2016-10-01	12420
2017-01-01	12657
2017-04-01	14814
2017-07-01	13437
2017-10-01	10491
2018-01-01	6816
2018-04-01	7600