Quarter	Billions of US Dollars
1987-01-01	0.20000
1987-04-01	0.10395
1987-07-01	0.07610
1987-10-01	0.00121
1988-01-01	0.00129
1988-04-01	0.00133
1988-07-01	0.00126
1988-10-01	0.00136
1989-01-01	0.00134
1989-04-01	0.00126
1989-07-01	0.00124
1989-10-01	0.00124
1990-01-01	0.00122
1990-04-01	-0.02197
1990-07-01	0.00126
1990-10-01	0.00142
1991-01-01	0.00140
1991-04-01	0.00137
1991-07-01	0.00140
1991-10-01	-0.06821
1992-01-01	0.00152
1992-04-01	-0.14501
1993-07-01	-0.22337
1994-01-01	-0.20000
1997-07-01	-0.07500
2009-10-01	0.22613
2010-10-01	0.04086
2011-01-01	0.65718
2011-04-01	-0.30681
2011-07-01	0.20033
2011-10-01	-0.28419
2012-01-01	0.27773
2012-04-01	0.11241
2012-07-01	-0.03951
2012-10-01	0.07334
2013-01-01	-0.07243
2013-04-01	0.05259
2013-07-01	0.13597
2013-10-01	0.24996
2014-01-01	-0.01074
2014-04-01	0.16025
2014-07-01	-0.08911
2014-10-01	-0.28047
2015-01-01	0.06983
2015-04-01	-0.00390