Quarter	Billions of US Dollars
1987-01-01	0.14700
1987-04-01	0.14400
1987-07-01	0.14800
1987-10-01	0.11100
1988-01-01	0.20000
1988-04-01	0.21200
1988-07-01	0.12700
1988-10-01	0.19100
1989-01-01	0.22200
1989-04-01	0.16700
1989-07-01	0.17400
1989-10-01	0.18800
1990-01-01	0.18700
1990-04-01	0.10100
1990-07-01	0.02500
1990-10-01	0.00400
1991-01-01	0.00500
1991-04-01	0.06900
1991-07-01	0.11000
1991-10-01	0.13900
1992-01-01	0.13400
1992-04-01	0.12900
1992-07-01	0.14900
1992-10-01	0.15500
1993-01-01	0.13800
1993-04-01	0.13800
1993-07-01	0.15494
1993-10-01	0.16738
1994-01-01	0.22605
1994-04-01	0.19155
1994-07-01	0.25000
1994-10-01	0.25400
1995-01-01	0.25178
1995-04-01	0.25978
1995-07-01	0.25162
1995-10-01	0.34962
1996-01-01	0.35751
1996-04-01	0.34751
1996-07-01	0.35540
1996-10-01	0.36750
1997-01-01	0.35840
1997-04-01	0.34390
1997-07-01	0.32338
1997-10-01	0.16970
1998-01-01	0.22350
1998-04-01	0.27000
1998-07-01	0.25702
1998-10-01	0.07352
1999-01-01	0.06068
1999-04-01	0.27068
1999-07-01	0.25435
1999-10-01	0.15185
2000-01-01	0.17401
2000-04-01	0.14501
2000-07-01	0.13567
2000-10-01	0.13051
2001-01-01	0.16584
2001-04-01	0.09884
2005-07-01	0.79614
2005-10-01	1.39807
2006-01-01	2.40430
2006-04-01	1.97203
2006-07-01	3.13810
2006-10-01	5.03110
2007-01-01	6.18160
2007-04-01	6.28405
2007-07-01	5.69515
2007-10-01	3.73762
2008-01-01	5.28986
2008-04-01	4.70439
2008-07-01	4.87429
2008-10-01	1.30990
2009-01-01	1.17716
2009-04-01	1.16468
2009-07-01	1.32298
2009-10-01	1.17951
2010-01-01	0.57584
2010-04-01	0.34251
2010-07-01	0.39906
2010-10-01	0.22482
2011-01-01	0.43821
2011-04-01	0.42115
2011-07-01	0.90007
2011-10-01	0.75168
2012-01-01	2.05561
2012-04-01	2.74933
2012-07-01	2.86570
2012-10-01	3.36215
2013-01-01	4.02563
2013-04-01	4.97785
2013-07-01	5.76034
2013-10-01	6.36544
2014-01-01	5.52830
2014-04-01	6.63477
2014-07-01	6.86057
2014-10-01	6.97717
2015-01-01	6.95685
2015-04-01	7.46262