Quarter	Millions of US Dollars
1981-10-01	106
1985-01-01	150
1985-10-01	50
1986-01-01	174
1987-01-01	86
1988-04-01	109
1988-07-01	156
1988-10-01	18
1989-04-01	150
1989-10-01	200
1990-01-01	125
1990-07-01	149
1990-10-01	236
1992-01-01	-150
1992-10-01	-81
1993-01-01	-208
1993-07-01	65
1993-10-01	165
1994-01-01	27
1994-04-01	135
1994-07-01	260
1994-10-01	-200
1995-07-01	150
1996-01-01	120
1996-04-01	200
1996-07-01	300
1996-10-01	222
1997-01-01	364
1997-04-01	286
1997-07-01	613
1997-10-01	40
1998-04-01	-114
1998-07-01	-208
1999-01-01	-50
1999-04-01	-401
1999-07-01	-324
1999-10-01	-214
2000-01-01	-309
2000-04-01	-35
2001-01-01	-21
2001-04-01	-109
2002-01-01	-150
2002-07-01	-42
2002-10-01	77
2003-07-01	100
2003-10-01	-201
2004-01-01	498
2004-04-01	850
2004-07-01	213
2004-10-01	598
2005-01-01	627
2005-04-01	500
2005-07-01	576
2005-10-01	672
2006-01-01	2540
2006-04-01	2227
2006-07-01	549
2006-10-01	737
2007-01-01	2056
2007-04-01	1632
2007-07-01	1759
2007-10-01	1024
2008-01-01	171
2008-04-01	173
2008-07-01	-99
2008-10-01	-82
2009-01-01	-387
2009-04-01	-787
2009-07-01	772
2009-10-01	1703
2010-01-01	81
2010-04-01	-362
2010-07-01	-605
2010-10-01	-583
2011-01-01	-2226
2011-04-01	-1890
2011-07-01	1289
2011-10-01	-564
2012-01-01	-1809
2012-04-01	-1900
2012-07-01	-1956
2012-10-01	1241
2013-01-01	582
2013-04-01	660
2013-07-01	1000
2014-01-01	124
2014-04-01	532
2014-07-01	3116
2014-10-01	-497
2015-01-01	1339
2015-04-01	1773
2015-07-01	800
2015-10-01	-200
2016-01-01	239
2016-04-01	5
2016-07-01	893
2016-10-01	1035
2017-01-01	1461
2017-04-01	1555
2017-07-01	220
2017-10-01	1459
2018-01-01	-400
2018-04-01	-547