Quarter	Billions of US Dollars
1987-01-01	0.06710
1987-10-01	0.04410
1988-04-01	0.07230
1989-01-01	0.04863
1990-10-01	-0.03930
1991-04-01	0.03390
1991-10-01	-0.04182
1992-10-01	-0.03601
1993-04-01	0.06560
1993-07-01	0.08970
1993-10-01	0.06950
1994-01-01	0.05404
1995-04-01	0.08640
1995-07-01	0.08640
1996-01-01	-0.11337
1996-07-01	-0.10793
1997-01-01	-0.06957
1998-04-01	-0.05358
1999-10-01	-0.06488
2000-01-01	-0.06141
2001-04-01	-0.08568
2002-07-01	-0.06718
2003-04-01	-0.07478
2006-04-01	0.20580
2007-04-01	0.20573
2010-04-01	0.18459
2011-04-01	-0.30992
2012-04-01	-0.26695
2012-07-01	0.25895
2013-01-01	0.32841
2015-04-01	0.20791