Quarter	Billions of US Dollars
1987-01-01	3.017
1987-04-01	3.331
1987-07-01	4.001
1987-10-01	4.270
1988-01-01	4.884
1988-04-01	4.350
1988-07-01	5.536
1988-10-01	5.301
1989-01-01	5.377
1989-04-01	5.347
1989-07-01	5.127
1989-10-01	4.545
1990-01-01	5.875
1990-04-01	5.710
1990-07-01	6.933
1990-10-01	6.514
1991-01-01	6.890
1991-04-01	6.891
1991-07-01	6.556
1991-10-01	7.031
1992-01-01	7.469
1992-04-01	7.505
1992-07-01	7.671
1992-10-01	6.384
1993-01-01	6.242
1993-04-01	6.235
1993-07-01	6.471
1993-10-01	6.088
1994-01-01	5.973
1994-04-01	6.623
1994-07-01	5.337
1994-10-01	4.375
1995-01-01	4.049
1995-04-01	4.767
1995-07-01	4.921
1995-10-01	3.449
1996-01-01	3.212
1996-04-01	3.408
1996-07-01	3.337
1996-10-01	3.297
1997-01-01	4.135
1997-04-01	6.239
1997-07-01	7.835
1997-10-01	7.052
1998-01-01	6.120
1998-04-01	7.131
1998-07-01	9.425
1998-10-01	14.402
1999-01-01	17.755
1999-04-01	20.512
1999-07-01	23.767
1999-10-01	24.831
2000-01-01	25.921
2000-04-01	33.350
2000-07-01	33.896
2000-10-01	41.998
2001-01-01	40.756
2001-04-01	38.910
2001-07-01	40.799
2001-10-01	41.608
2002-01-01	36.652
2002-04-01	39.689
2002-07-01	40.486
2002-10-01	45.647
2003-01-01	44.131
2003-04-01	41.026
2003-07-01	40.290
2003-10-01	49.580
2004-01-01	52.012
2004-04-01	52.998
2004-07-01	49.350
2004-10-01	49.705
2005-01-01	49.082
2005-04-01	44.032
2005-07-01	35.771
2005-10-01	37.302
2006-01-01	39.711
2006-04-01	49.147
2006-07-01	45.479
2006-10-01	44.603
2007-01-01	53.060
2007-04-01	59.305
2007-07-01	62.134
2007-10-01	65.660
2008-01-01	81.392
2008-04-01	82.025
2008-07-01	89.751
2008-10-01	92.488
2009-01-01	91.744
2009-04-01	87.380
2009-07-01	97.879
2009-10-01	87.405
2010-01-01	89.119
2010-04-01	76.466
2010-07-01	101.004
2010-10-01	102.655
2011-01-01	108.212
2011-04-01	111.741
2011-07-01	114.561
2011-10-01	114.146
2012-01-01	132.559
2012-04-01	121.865
2012-07-01	115.585
2012-10-01	118.003
2013-01-01	111.781
2013-04-01	114.511
2013-07-01	109.596
2013-10-01	90.807
2014-01-01	90.988
2014-04-01	100.164
2014-07-01	86.375
2014-10-01	74.146
2015-01-01	75.307
2015-04-01	72.729