Quarter	Millions of US Dollars
1986-04-01	250
1988-04-01	300
1988-10-01	319
1989-04-01	200
1989-07-01	412
1989-10-01	250
1990-01-01	200
1990-04-01	147
1990-07-01	150
1990-10-01	96
1991-04-01	267
1991-10-01	300
1992-01-01	234
1992-04-01	239
1992-07-01	1052
1992-10-01	981
1993-01-01	1043
1993-04-01	540
1993-07-01	596
1993-10-01	1537
1994-01-01	694
1994-04-01	250
1994-07-01	5118
1994-10-01	5840
1995-04-01	-302
1995-07-01	1548
1995-10-01	227
1996-01-01	435
1996-04-01	1259
1996-07-01	-264
1996-10-01	442
1997-01-01	2197
1997-04-01	3979
1997-07-01	2883
1997-10-01	677
1998-01-01	2711
1998-04-01	5606
1998-07-01	5446
1998-10-01	-2126
1999-01-01	1954
1999-04-01	1418
1999-07-01	288
1999-10-01	2677
2000-01-01	2464
2000-04-01	3778
2000-07-01	22461
2000-10-01	-333
2001-01-01	1100
2001-04-01	76
2001-07-01	72
2001-10-01	526
2002-01-01	1272
2002-04-01	-316
2002-07-01	1192
2002-10-01	-721
2003-01-01	3448
2003-04-01	337
2003-07-01	4076
2003-10-01	357
2004-01-01	3360
2004-04-01	5444
2004-07-01	728
2004-10-01	2129
2005-01-01	7602
2005-04-01	9722
2005-07-01	-3992
2005-10-01	2769
2006-01-01	7338
2006-04-01	-1895
2006-07-01	1498
2006-10-01	5114
2007-01-01	5267
2007-04-01	-1683
2007-07-01	-1631
2007-10-01	2809
2008-01-01	-3030
2008-04-01	10323
2008-07-01	704
2008-10-01	-599
2009-01-01	885
2009-04-01	3911
2009-07-01	4162
2009-10-01	4241
2010-01-01	9099
2010-04-01	5647
2010-07-01	7618
2010-10-01	1337
2011-01-01	9209
2011-04-01	7849
2011-07-01	1892
2011-10-01	549
2012-01-01	10494
2012-04-01	16485
2012-07-01	5327
2012-10-01	12329
2013-01-01	-117
2013-04-01	2112
2013-07-01	8561
2013-10-01	17144
2014-01-01	-9307
2014-04-01	-766
2014-07-01	1109
2014-10-01	812
2015-01-01	-141
2015-04-01	68
2015-07-01	386
2015-10-01	-16980
2016-01-01	1505
2016-04-01	7108
2016-07-01	-2385
2016-10-01	4797
2017-01-01	1580
2017-04-01	6440
2017-07-01	5993
2017-10-01	7329
2018-01-01	5423
2018-04-01	-8606