Quarter	Billions of US Dollars
1987-01-01	5.111
1987-04-01	5.566
1987-07-01	5.702
1987-10-01	6.124
1988-01-01	6.937
1988-04-01	7.579
1988-07-01	7.634
1988-10-01	8.302
1989-01-01	8.900
1989-04-01	8.482
1989-07-01	8.877
1989-10-01	10.588
1990-01-01	10.498
1990-04-01	11.614
1990-07-01	12.685
1990-10-01	12.997
1991-01-01	12.158
1991-04-01	13.379
1991-07-01	14.314
1991-10-01	15.147
1992-01-01	15.380
1992-04-01	16.803
1992-07-01	18.875
1992-10-01	17.686
1993-01-01	19.244
1993-04-01	19.972
1993-07-01	23.948
1993-10-01	24.638
1994-01-01	26.775
1994-04-01	28.913
1994-07-01	28.861
1994-10-01	28.546
1995-01-01	29.023
1995-04-01	28.646
1995-07-01	28.652
1995-10-01	28.756
1996-01-01	30.548
1996-04-01	30.807
1996-07-01	32.309
1996-10-01	32.937
1997-01-01	31.806
1997-04-01	32.219
1997-07-01	32.014
1997-10-01	31.209
1998-01-01	29.807
1998-04-01	28.992
1998-07-01	28.888
1998-10-01	29.841
1999-01-01	28.434
1999-04-01	29.877
1999-07-01	32.440
1999-10-01	34.133
2000-01-01	36.914
2000-04-01	39.709
2000-07-01	39.485
2000-10-01	40.428
2001-01-01	36.461
2001-04-01	35.586
2001-07-01	36.538
2001-10-01	36.847
2002-01-01	36.844
2002-04-01	42.414
2002-07-01	42.094
2002-10-01	41.610
2003-01-01	42.909
2003-04-01	46.655
2003-07-01	50.757
2003-10-01	57.052
2004-01-01	56.970
2004-04-01	54.294
2004-07-01	58.087
2004-10-01	61.982
2005-01-01	60.439
2005-04-01	62.661
2005-07-01	62.370
2005-10-01	62.167
2006-01-01	67.222
2006-04-01	70.872
2006-07-01	72.522
2006-10-01	75.008
2007-01-01	78.930
2007-04-01	82.641
2007-07-01	86.204
2007-10-01	91.425
2008-01-01	94.930
2008-04-01	97.318
2008-07-01	94.815
2008-10-01	90.416
2009-01-01	91.677
2009-04-01	99.372
2009-07-01	111.536
2009-10-01	117.009
2010-01-01	116.491
2010-04-01	111.742
2010-07-01	121.382
2010-10-01	122.686
2011-01-01	127.380
2011-04-01	134.474
2011-07-01	129.245
2011-10-01	124.383
2012-01-01	127.991
2012-04-01	129.219
2012-07-01	133.198
2012-10-01	141.217
2013-01-01	143.617
2013-04-01	143.261
2013-07-01	147.062
2013-10-01	144.110
2014-01-01	145.846
2014-04-01	142.113
2014-07-01	138.531
2014-10-01	136.394
2015-01-01	125.570
2015-04-01	132.883