Quarter	Billions of US Dollars
1987-01-01	0.22400
1987-04-01	0.19500
1987-07-01	0.18000
1987-10-01	0.17400
1988-01-01	0.24700
1988-04-01	0.24700
1988-07-01	0.24400
1988-10-01	0.30700
1989-01-01	0.29700
1989-04-01	0.34400
1989-07-01	0.14900
1989-10-01	0.08500
1990-01-01	0.04000
1990-04-01	0.01500
1990-07-01	0.01000
1990-10-01	0.08100
1991-01-01	0.07300
1991-10-01	0.04400
1992-01-01	0.04400
1993-10-01	0.01600
1994-01-01	0.01600
1994-04-01	0.02000
1994-07-01	0.02000
1994-10-01	0.02000
1995-10-01	0.03335
1996-01-01	0.02870
1996-04-01	0.07000
1996-07-01	0.05000
1998-01-01	0.04722
1998-04-01	0.04722
1998-10-01	0.00899
1999-01-01	0.01926
1999-04-01	0.01430
1999-07-01	0.01473
1999-10-01	0.01806
2000-01-01	0.04127
2000-04-01	0.04348
2000-07-01	0.04418
2000-10-01	0.00965
2001-04-01	0.01348
2001-07-01	0.01413
2001-10-01	0.01381
2002-01-01	0.02245
2002-04-01	0.02495
2002-07-01	0.03831
2002-10-01	0.03499
2003-01-01	0.04187
2003-04-01	0.05563
2003-07-01	0.06497
2003-10-01	0.07547
2004-01-01	0.09779
2004-04-01	0.10089
2004-07-01	0.10672
2004-10-01	0.11714
2005-01-01	0.05575
2005-04-01	0.01209
2005-07-01	0.00201
2005-10-01	0.00201
2006-01-01	0.00201
2006-07-01	0.04320
2006-10-01	0.13412
2007-01-01	0.08942
2007-04-01	0.09287
2007-07-01	0.10201
2007-10-01	0.13215
2008-01-01	0.13178
2008-04-01	0.12737
2008-07-01	0.29591
2008-10-01	0.00517
2011-07-01	0.00700
2011-10-01	0.11897
2012-01-01	0.08665
2012-04-01	0.22908
2012-07-01	0.26978
2012-10-01	0.12254
2013-01-01	0.10362
2013-04-01	0.67148
2013-07-01	1.42201
2013-10-01	1.63042
2014-01-01	1.78001
2014-04-01	2.81933
2014-07-01	3.58184
2014-10-01	3.92323
2015-01-01	3.93597
2015-04-01	3.75572