Quarter	Millions of US Dollars
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	10
1976-10-01	10
1977-01-01	10
1977-04-01	10
1977-07-01	0
1977-10-01	0
1978-01-01	28
1978-04-01	54
1978-07-01	61
1978-10-01	61
1979-01-01	30
1979-04-01	105
1979-07-01	220
1979-10-01	221
1980-01-01	238
1980-04-01	190
1980-07-01	75
1980-10-01	154
1981-01-01	603
1981-04-01	650
1981-07-01	808
1981-10-01	767
1982-01-01	339
1982-04-01	503
1982-07-01	576
1982-10-01	887
1983-01-01	808
1983-04-01	593
1983-07-01	543
1983-10-01	368
1984-01-01	399
1984-04-01	404
1984-07-01	514
1984-10-01	859
1985-01-01	1177
1985-04-01	1911
1985-07-01	2040
1985-10-01	2109
1986-01-01	2087
1986-04-01	1382
1986-07-01	1592
1986-10-01	1155
1987-01-01	1218
1987-04-01	1522
1987-07-01	1590
1987-10-01	2017
1988-01-01	1872
1988-04-01	2658
1988-07-01	2691
1988-10-01	3576
1989-01-01	3945
1989-04-01	3460
1989-07-01	4799
1989-10-01	5171
1990-01-01	5403
1990-04-01	7087
1990-07-01	6981
1990-10-01	7429
1991-01-01	7735
1991-04-01	8370
1991-07-01	10071
1991-10-01	9327
1992-01-01	9868
1992-04-01	9189
1992-07-01	8544
1992-10-01	8897
1993-01-01	8450
1993-04-01	7430
1993-07-01	32862
1993-10-01	30817
1994-01-01	31531
1994-04-01	28316
1994-07-01	26272
1994-10-01	25808
1995-01-01	27816
1995-04-01	31379
1995-07-01	33717
1995-10-01	32910
1996-01-01	35212
1996-04-01	34502
1996-07-01	23417
1996-10-01	40604
1997-01-01	42003
1997-04-01	43196
1997-07-01	45196
1997-10-01	38945
1998-01-01	42017
1998-04-01	37450
1998-07-01	42317
1998-10-01	41250
1999-01-01	45564
1999-04-01	39846
1999-07-01	43983
1999-10-01	46428
2000-01-01	46810
2000-04-01	41853
2000-07-01	43172
2000-10-01	47838
2001-01-01	48375
2001-04-01	47880
2001-07-01	49414
2001-10-01	48914
2002-01-01	53315
2002-04-01	60297
2002-07-01	60109
2002-10-01	61162
2003-01-01	58310
2003-04-01	61210
2003-07-01	62182
2003-10-01	75153
2004-01-01	78940
2004-04-01	73738
2004-07-01	81463
2004-10-01	86777
2005-01-01	84105
2005-04-01	86835
2005-07-01	88543
2005-10-01	92182
2006-01-01	101847
2006-04-01	115464
2006-07-01	117568
2006-10-01	123336
2007-01-01	119040
2007-04-01	133738
2007-07-01	136455
2007-10-01	126543
2008-01-01	168829
2008-04-01	162331
2008-07-01	141192
2008-10-01	107694
2009-01-01	87285
2009-04-01	103821
2009-07-01	103878
2009-10-01	107301
2010-01-01	112428
2010-04-01	119799
2010-07-01	127983
2010-10-01	121754
2011-01-01	116923
2011-04-01	119335
2011-07-01	109018
2011-10-01	111725
2012-01-01	108010
2012-04-01	107178
2012-07-01	103725
2012-10-01	106230
2013-01-01	117255
2013-04-01	114853
2013-07-01	134858
2013-10-01	132862
2014-01-01	132358
2014-04-01	136927
2014-07-01	128853
2014-10-01	117310
2015-01-01	106601
2015-04-01	105405
2015-07-01	91628
2015-10-01	109709
2016-01-01	130759
2016-04-01	132777
2016-07-01	135586
2016-10-01	120216
2017-01-01	106091
2017-04-01	107132
2017-07-01	95580
2017-10-01	90417
2018-01-01	99958
2018-04-01	99759