Quarter	Millions of US Dollars
1968-07-01	40
1969-01-01	95
1969-04-01	15
1969-07-01	20
1971-10-01	15
1972-01-01	20
1972-04-01	95
1972-07-01	234
1972-10-01	72
1973-01-01	186
1973-04-01	106
1973-07-01	57
1973-10-01	92
1974-01-01	19
1974-04-01	105
1974-07-01	182
1974-10-01	306
1975-01-01	214
1975-04-01	258
1975-07-01	167
1975-10-01	84
1976-01-01	71
1976-04-01	391
1976-07-01	190
1976-10-01	113
1977-01-01	262
1977-04-01	210
1977-07-01	320
1977-10-01	118
1978-01-01	130
1978-04-01	204
1978-07-01	334
1978-10-01	115
1979-01-01	776
1979-04-01	240
1979-07-01	-203
1979-10-01	-61
1980-01-01	152
1980-04-01	815
1980-07-01	734
1980-10-01	921
1981-01-01	370
1981-04-01	410
1981-07-01	335
1981-10-01	935
1982-01-01	134
1982-04-01	410
1982-07-01	241
1982-10-01	1603
1983-01-01	1527
1983-04-01	1120
1983-07-01	577
1983-10-01	2142
1984-01-01	2485
1984-04-01	1560
1984-07-01	1619
1984-10-01	1366
1985-01-01	883
1985-04-01	1031
1985-07-01	419
1985-10-01	-366
1986-01-01	1070
1986-04-01	1790
1986-07-01	1981
1986-10-01	1469
1987-01-01	2760
1987-04-01	2574
1987-07-01	894
1987-10-01	-453
1988-01-01	1951
1988-04-01	2988
1988-07-01	2042
1988-10-01	3828
1989-01-01	1828
1989-04-01	3194
1989-07-01	680
1989-10-01	1794
1990-01-01	3903
1990-04-01	373
1990-07-01	1262
1990-10-01	1708
1991-01-01	3530
1991-04-01	1434
1991-07-01	2064
1991-10-01	2100
1992-01-01	2817
1992-04-01	1844
1992-07-01	1232
1992-10-01	2611
1993-01-01	3853
1993-04-01	3778
1993-07-01	11364
1993-10-01	5857
1994-01-01	5506
1994-04-01	3414
1994-07-01	5597
1994-10-01	5344
1995-01-01	5863
1995-04-01	9196
1995-07-01	5230
1995-10-01	5343
1996-01-01	12222
1996-04-01	10488
1996-07-01	7114
1996-10-01	7093
1997-01-01	13173
1997-04-01	9066
1997-07-01	13053
1997-10-01	5943
1998-01-01	12802
1998-04-01	17689
1998-07-01	15382
1998-10-01	9163
1999-01-01	24102
1999-04-01	42253
1999-07-01	29723
1999-10-01	16319
2000-01-01	14753
2000-04-01	21891
2000-07-01	34642
2000-10-01	32819
2001-01-01	23261
2001-04-01	22369
2001-07-01	14728
2001-10-01	29161
2002-01-01	16425
2002-04-01	18764
2002-07-01	23680
2002-10-01	16653
2003-01-01	22040
2003-04-01	32374
2003-07-01	13339
2003-10-01	41895
2004-01-01	5843
2004-04-01	17988
2004-07-01	242
2004-10-01	23092
2005-01-01	22178
2005-04-01	19433
2005-07-01	-103
2005-10-01	43841
2006-01-01	30844
2006-04-01	56138
2006-07-01	35033
2006-10-01	62510
2007-01-01	69757
2007-04-01	56184
2007-07-01	13944
2007-10-01	30415
2008-01-01	17919
2008-04-01	72236
2008-07-01	15479
2008-10-01	27793
2009-01-01	83720
2009-04-01	64169
2009-07-01	27039
2009-10-01	11058
2010-01-01	64773
2010-04-01	-26223
2010-07-01	69950
2010-10-01	17288
2011-01-01	16544
2011-04-01	23184
2011-07-01	14952
2011-10-01	47372
2012-01-01	47679
2012-04-01	-6216
2012-07-01	32576
2012-10-01	23258
2013-01-01	-745
2013-04-01	28986
2013-07-01	20862
2013-10-01	-18783
2014-01-01	3131
2014-04-01	7643
2014-07-01	-10959
2014-10-01	-4390
2015-01-01	-903
2015-04-01	21775
2015-07-01	-6378
2015-10-01	-23110
2016-01-01	29949
2016-04-01	18751
2016-07-01	36329
2016-10-01	-23156
2017-01-01	50914
2017-04-01	28146
2017-07-01	32577
2017-10-01	-2535
2018-01-01	22079
2018-04-01	20732