Quarter	Millions of US Dollars
1968-01-01	60
1968-04-01	60
1972-01-01	46
1972-04-01	103
1972-10-01	30
1973-01-01	37
1973-10-01	98
1974-01-01	20
1974-04-01	23
1974-07-01	33
1974-10-01	33
1975-01-01	88
1975-04-01	61
1975-07-01	100
1975-10-01	29
1976-01-01	67
1976-04-01	109
1976-07-01	31
1976-10-01	99
1977-01-01	35
1977-04-01	342
1977-07-01	33
1977-10-01	11
1978-01-01	166
1978-04-01	202
1978-07-01	119
1978-10-01	69
1979-01-01	57
1979-04-01	64
1979-07-01	38
1979-10-01	-25
1980-01-01	-12
1980-04-01	-5
1980-07-01	86
1980-10-01	65
1981-01-01	-11
1981-04-01	114
1981-07-01	92
1981-10-01	14
1982-01-01	104
1982-04-01	28
1982-07-01	485
1982-10-01	396
1983-01-01	1022
1983-04-01	695
1983-07-01	5
1983-10-01	785
1984-01-01	883
1984-04-01	222
1984-07-01	483
1984-10-01	553
1985-01-01	516
1985-04-01	556
1985-07-01	885
1985-10-01	868
1986-01-01	1702
1986-04-01	3702
1986-07-01	2297
1986-10-01	2071
1987-01-01	3259
1987-04-01	1741
1987-07-01	2221
1987-10-01	829
1988-01-01	2047
1988-04-01	1926
1988-07-01	2266
1988-10-01	2370
1989-01-01	1824
1989-04-01	2764
1989-07-01	1505
1989-10-01	1231
1990-01-01	2023
1990-04-01	1302
1990-07-01	1568
1990-10-01	257
1991-01-01	1308
1991-04-01	2039
1991-07-01	1520
1991-10-01	4252
1992-01-01	2822
1992-04-01	3858
1992-07-01	2728
1992-10-01	3663
1993-01-01	5693
1993-04-01	5905
1993-07-01	8563
1993-10-01	8860
1994-01-01	12377
1994-04-01	5990
1994-07-01	7275
1994-10-01	11380
1995-01-01	11492
1995-04-01	14024
1995-07-01	13127
1995-10-01	15878
1996-01-01	21213
1996-04-01	17327
1996-07-01	17137
1996-10-01	22438
1997-01-01	28974
1997-04-01	20702
1997-07-01	14818
1997-10-01	8600
1998-01-01	27130
1998-04-01	21637
1998-07-01	16771
1998-10-01	1572
1999-01-01	40456
1999-04-01	29185
1999-07-01	49895
1999-10-01	26943
2000-01-01	45881
2000-04-01	51059
2000-07-01	48989
2000-10-01	41964
2001-01-01	48079
2001-04-01	28053
2001-07-01	13774
2001-10-01	24011
2002-01-01	35392
2002-04-01	41165
2002-07-01	30791
2002-10-01	17833
2003-01-01	51288
2003-04-01	34507
2003-07-01	14478
2003-10-01	44813
2004-01-01	48197
2004-04-01	43624
2004-07-01	61435
2004-10-01	34283
2005-01-01	60956
2005-04-01	59045
2005-07-01	-11872
2005-10-01	45978
2006-01-01	72498
2006-04-01	60568
2006-07-01	48485
2006-10-01	47114
2007-01-01	52768
2007-04-01	68261
2007-07-01	1312
2007-10-01	21667
2008-01-01	-822
2008-04-01	36004
2008-07-01	-25487
2008-10-01	2294
2009-01-01	-9878
2009-04-01	2380
2009-07-01	-28039
2009-10-01	-29186
2010-01-01	5681
2010-04-01	-24646
2010-07-01	-909
2010-10-01	-39190
2011-01-01	-7257
2011-04-01	3929
2011-07-01	36887
2011-10-01	19289
2012-01-01	16917
2012-04-01	12517
2012-07-01	-36907
2012-10-01	21821
2013-01-01	-7459
2013-04-01	-2426
2013-07-01	-30056
2013-10-01	-19362
2014-01-01	-16923
2014-04-01	19161
2014-07-01	6881
2014-10-01	11730
2015-01-01	1643
2015-04-01	-1365
2015-07-01	-6497
2015-10-01	-50194
2016-01-01	32406
2016-04-01	3146
2016-07-01	24309
2016-10-01	-10848
2017-01-01	32274
2017-04-01	10752
2017-07-01	10716
2017-10-01	74
2018-01-01	20225
2018-04-01	14828