Quarter	Millions of US Dollars
1972-04-01	20
1973-07-01	27
1975-01-01	24
1975-04-01	12
1975-10-01	19
1976-04-01	25
1976-10-01	76
1977-04-01	45
1977-07-01	52
1978-07-01	-48
1981-01-01	75
1981-10-01	30
1982-04-01	38
1982-07-01	7
1982-10-01	-20
1983-04-01	-25
1983-10-01	-12
1984-07-01	-28
1984-10-01	75
1985-01-01	-15
1985-04-01	-26
1985-10-01	40
1986-01-01	-75
1986-07-01	73
1986-10-01	55
1987-01-01	37
1987-04-01	137
1987-10-01	212
1988-01-01	156
1988-04-01	6
1988-07-01	-24
1989-04-01	158
1989-07-01	71
1990-01-01	211
1990-04-01	142
1990-07-01	92
1990-10-01	128
1991-01-01	-67
1991-04-01	169
1991-07-01	89
1991-10-01	-85
1992-01-01	-78
1992-04-01	-51
1992-07-01	79
1992-10-01	-23
1993-01-01	182
1993-04-01	3
1993-07-01	319
1993-10-01	827
1994-01-01	827
1994-04-01	523
1994-07-01	499
1994-10-01	289
1995-01-01	-203
1995-04-01	-317
1995-07-01	57
1995-10-01	-10
1996-01-01	171
1996-04-01	758
1996-07-01	-129
1996-10-01	238
1997-01-01	410
1997-04-01	146
1997-07-01	1419
1997-10-01	-185
1998-01-01	-122
1998-04-01	690
1998-07-01	224
1998-10-01	172
1999-01-01	889
1999-04-01	283
1999-07-01	738
1999-10-01	1448
2000-01-01	559
2000-04-01	1897
2000-07-01	446
2000-10-01	650
2001-01-01	-769
2001-04-01	1945
2001-07-01	243
2001-10-01	4516
2002-01-01	2056
2002-04-01	1721
2002-07-01	-1059
2002-10-01	-42
2003-01-01	-273
2003-04-01	142
2003-07-01	1138
2003-10-01	3589
2004-01-01	449
2004-04-01	622
2004-07-01	-566
2004-10-01	368
2005-01-01	2461
2005-04-01	275
2005-07-01	214
2005-10-01	-277
2006-01-01	388
2006-04-01	1389
2006-07-01	2927
2006-10-01	1326
2007-01-01	1732
2007-04-01	1499
2007-07-01	329
2007-10-01	1715
2008-01-01	665
2008-04-01	5061
2008-07-01	2140
2008-10-01	369
2009-01-01	-225
2009-04-01	3888
2009-07-01	1136
2009-10-01	1209
2010-01-01	547
2010-04-01	1400
2010-07-01	1384
2010-10-01	929
2011-01-01	-593
2011-04-01	5929
2011-07-01	560
2011-10-01	-1565
2012-01-01	-1199
2012-04-01	794
2012-07-01	3073
2012-10-01	4050
2013-01-01	3596
2013-04-01	4308
2013-07-01	1004
2013-10-01	1773
2014-01-01	2215
2014-04-01	3434
2014-07-01	4089
2014-10-01	1670
2015-01-01	1084
2015-04-01	4520
2015-07-01	1523
2015-10-01	-342
2016-01-01	757
2016-04-01	-476
2016-07-01	1618
2016-10-01	2029
2017-01-01	-681
2017-04-01	2286
2017-07-01	5775
2017-10-01	3106
2018-01-01	-320
2018-04-01	10556