Quarter	Billions of US Dollars
1987-01-01	6.194
1987-04-01	6.801
1987-07-01	7.244
1987-10-01	7.744
1988-01-01	8.099
1988-04-01	8.140
1988-07-01	8.422
1988-10-01	9.302
1989-01-01	9.615
1989-04-01	9.285
1989-07-01	9.842
1989-10-01	10.437
1990-01-01	10.461
1990-04-01	10.891
1990-07-01	12.082
1990-10-01	12.206
1991-01-01	11.475
1991-04-01	11.250
1991-07-01	11.873
1991-10-01	11.912
1992-01-01	11.680
1992-04-01	11.382
1992-07-01	12.076
1992-10-01	10.903
1993-01-01	10.645
1993-04-01	11.254
1993-07-01	19.825
1993-10-01	20.550
1994-01-01	21.494
1994-04-01	22.433
1994-07-01	23.466
1994-10-01	23.928
1995-01-01	25.157
1995-04-01	24.987
1995-07-01	25.267
1995-10-01	25.437
1996-01-01	24.167
1996-04-01	22.971
1996-07-01	24.139
1996-10-01	24.475
1997-01-01	24.214
1997-04-01	24.065
1997-07-01	23.437
1997-10-01	21.619
1998-01-01	21.374
1998-04-01	21.797
1998-07-01	21.724
1998-10-01	22.698
1999-01-01	21.247
1999-04-01	22.481
1999-07-01	25.919
1999-10-01	26.749
2000-01-01	28.003
2000-04-01	29.821
2000-07-01	30.355
2000-10-01	27.965
2001-01-01	29.158
2001-04-01	32.542
2001-07-01	34.430
2001-10-01	33.943
2002-01-01	36.529
2002-04-01	37.790
2002-07-01	39.735
2002-10-01	42.618
2003-01-01	44.602
2003-04-01	47.750
2003-07-01	53.733
2003-10-01	58.229
2004-01-01	66.973
2004-04-01	68.965
2004-07-01	76.788
2004-10-01	83.889
2005-01-01	87.933
2005-04-01	92.049
2005-07-01	93.976
2005-10-01	97.475
2006-01-01	105.729
2006-04-01	113.938
2006-07-01	122.846
2006-10-01	137.588
2007-01-01	158.957
2007-04-01	176.771
2007-07-01	184.155
2007-10-01	184.520
2008-01-01	189.683
2008-04-01	186.707
2008-07-01	178.328
2008-10-01	171.268
2009-01-01	168.133
2009-04-01	178.099
2009-07-01	184.691
2009-10-01	188.707
2010-01-01	185.912
2010-04-01	180.571
2010-07-01	192.942
2010-10-01	196.708
2011-01-01	202.509
2011-04-01	209.052
2011-07-01	203.043
2011-10-01	206.057
2012-01-01	211.550
2012-04-01	207.465
2012-07-01	222.318
2012-10-01	222.921
2013-01-01	217.376
2013-04-01	219.998
2013-07-01	222.231
2013-10-01	223.928
2014-01-01	225.667
2014-04-01	227.408
2014-07-01	221.641
2014-10-01	215.199
2015-01-01	205.683
2015-04-01	213.731