Quarter	Millions of US Dollars
1991-07-01	29
1991-10-01	50
1992-04-01	300
1992-07-01	740
1993-01-01	500
1993-07-01	30
1993-10-01	23
1994-01-01	-58
1994-04-01	-38
1994-07-01	-7
1994-10-01	654
1995-01-01	1249
1995-04-01	714
1995-07-01	1738
1995-10-01	138
1996-01-01	2847
1996-04-01	140
1996-07-01	811
1996-10-01	870
1997-01-01	2849
1997-04-01	109
1997-07-01	927
1997-10-01	-16
1998-01-01	1108
1998-04-01	61
1998-07-01	4
1999-01-01	113
1999-04-01	797
1999-07-01	1759
1999-10-01	-493
2000-01-01	-90
2000-04-01	713
2000-07-01	-304
2000-10-01	56
2001-01-01	384
2001-04-01	519
2001-07-01	2
2001-10-01	-391
2002-01-01	-1876
2002-04-01	-63
2002-07-01	-878
2002-10-01	-1164
2003-01-01	-1320
2003-04-01	-439
2003-07-01	1925
2003-10-01	632
2004-01-01	-157
2004-04-01	-224
2004-07-01	-211
2004-10-01	-127
2005-01-01	-147
2005-04-01	-1269
2005-07-01	-568
2005-10-01	-556
2006-01-01	-1376
2006-04-01	-718
2006-07-01	-167
2006-10-01	-33
2007-01-01	-774
2007-04-01	-40
2007-07-01	-121
2007-10-01	46
2008-01-01	-761
2008-04-01	201
2008-07-01	-29
2008-10-01	-673
2009-01-01	-27
2009-04-01	-391
2009-07-01	-1637
2009-10-01	-56
2010-07-01	-10
2011-01-01	-80
2011-04-01	-25
2011-07-01	-399
2012-07-01	253
2013-04-01	-139
2013-07-01	-1317
2015-01-01	-18
2016-01-01	-347
2018-01-01	-899
2018-04-01	-9