Quarter	Millions of US Dollars
1988-07-01	2211
1988-10-01	5819
1989-01-01	-1941
1989-04-01	-2288
1989-07-01	1749
1989-10-01	6922
1990-01-01	854
1990-04-01	-8308
1990-07-01	5102
1990-10-01	7197
1991-01-01	1831
1991-04-01	-919
1991-07-01	8608
1991-10-01	8523
1992-01-01	-1067
1992-04-01	2525
1992-07-01	2233
1992-10-01	7167
1993-01-01	5047
1993-04-01	840
1993-07-01	7603
1993-10-01	5234
1994-01-01	-3016
1994-04-01	-4213
1994-07-01	1368
1994-10-01	4070
1995-01-01	895
1995-04-01	3724
1995-07-01	-511
1995-10-01	1424
1996-01-01	-1460
1996-04-01	-2610
1996-07-01	4391
1996-10-01	3232
1997-01-01	-3664
1997-04-01	-848
1997-07-01	2151
1997-10-01	-3921
1998-01-01	-587
1998-04-01	-3604
1998-07-01	3125
1998-10-01	-2613
1999-01-01	-525
1999-04-01	-5531
1999-07-01	-701
1999-10-01	-3666
2000-01-01	-1420
2000-04-01	-2268
2000-07-01	-1292
2000-10-01	-827
2001-01-01	-51
2001-04-01	-2639
2001-07-01	1112
2001-10-01	-1664
2002-01-01	-2371
2002-04-01	738
2002-07-01	6322
2002-10-01	-2775
2003-01-01	-2036
2003-04-01	83
2003-07-01	-3423
2003-10-01	-1548
2004-01-01	1983
2004-04-01	-1938
2004-07-01	-1623
2004-10-01	2741
2005-01-01	431
2005-04-01	727
2005-07-01	-316
2005-10-01	870
2006-01-01	3227
2006-04-01	-6262
2006-07-01	5022
2006-10-01	-4007
2007-01-01	-1621
2007-04-01	3384
2007-07-01	7913
2007-10-01	-1428
2008-01-01	1187
2008-04-01	5201
2008-07-01	7338
2008-10-01	12554
2009-01-01	19349
2009-04-01	32321
2009-07-01	9622
2009-10-01	20358
2010-01-01	24111
2010-04-01	23977
2010-07-01	14127
2010-10-01	13790
2011-01-01	26742
2011-04-01	11618
2011-07-01	44782
2011-10-01	27104
2012-01-01	22257
2012-04-01	17265
2012-07-01	28791
2012-10-01	11993
2013-01-01	13567
2013-04-01	-9867
2013-07-01	22243
2013-10-01	8795
2014-01-01	23316
2014-04-01	22793
2014-07-01	25911
2014-10-01	28472
2015-01-01	25617
2015-04-01	-17861
2015-07-01	30931
2015-10-01	-5380
2016-01-01	26981
2016-04-01	4550
2016-07-01	22267
2016-10-01	-9846
2017-01-01	16561
2017-04-01	12673
2017-07-01	-2923
2017-10-01	15438
2018-01-01	6482