Quarter	Billions of US Dollars
1987-01-01	0.757
1987-04-01	0.720
1987-07-01	0.704
1987-10-01	0.771
1988-01-01	1.110
1988-04-01	1.134
1988-07-01	1.430
1988-10-01	1.634
1989-01-01	2.088
1989-04-01	2.024
1989-07-01	2.546
1989-10-01	2.747
1990-01-01	2.940
1990-04-01	2.963
1990-07-01	3.162
1990-10-01	3.343
1991-01-01	3.023
1991-04-01	2.866
1991-07-01	3.177
1991-10-01	3.453
1992-01-01	3.365
1992-04-01	3.466
1992-07-01	3.705
1992-10-01	3.492
1993-01-01	3.556
1993-04-01	3.375
1993-07-01	3.420
1993-10-01	3.277
1994-01-01	3.107
1994-04-01	3.127
1994-07-01	3.149
1994-10-01	3.149
1995-01-01	3.012
1995-04-01	3.050
1995-07-01	2.433
1995-10-01	2.353
1996-01-01	2.259
1996-04-01	2.231
1996-07-01	1.093
1996-10-01	1.019
1997-01-01	1.201
1997-04-01	1.551
1997-07-01	1.786
1997-10-01	2.032
1998-01-01	1.880
1998-04-01	1.687
1998-07-01	1.857
1998-10-01	1.776
1999-01-01	1.744
1999-04-01	1.679
1999-07-01	1.687
1999-10-01	1.786
2000-01-01	2.113
2000-04-01	2.438
2000-07-01	1.976
2000-10-01	1.853
2001-01-01	1.860
2001-04-01	2.299
2001-07-01	2.360
2001-10-01	2.424
2002-01-01	2.292
2002-04-01	2.572
2002-07-01	2.473
2002-10-01	2.530
2003-01-01	2.482
2003-04-01	2.829
2003-07-01	2.837
2003-10-01	4.764
2004-01-01	5.411
2004-04-01	5.697
2004-07-01	6.856
2004-10-01	8.224
2005-01-01	9.395
2005-04-01	12.530
2005-07-01	14.003
2005-10-01	17.353
2006-01-01	20.799
2006-04-01	23.015
2006-07-01	26.185
2006-10-01	33.158
2007-01-01	37.392
2007-04-01	46.291
2007-07-01	46.620
2007-10-01	51.537
2008-01-01	54.547
2008-04-01	63.232
2008-07-01	61.980
2008-10-01	59.485
2009-01-01	55.276
2009-04-01	56.804
2009-07-01	56.931
2009-10-01	55.741
2010-01-01	54.258
2010-04-01	49.946
2010-07-01	63.699
2010-10-01	73.793
2011-01-01	78.150
2011-04-01	82.871
2011-07-01	79.928
2011-10-01	79.319
2012-01-01	86.117
2012-04-01	91.816
2012-07-01	118.904
2012-10-01	134.697
2013-01-01	143.465
2013-04-01	145.743
2013-07-01	147.772
2013-10-01	155.763
2014-01-01	158.993
2014-04-01	161.784
2014-07-01	163.696
2014-10-01	165.134
2015-01-01	162.065
2015-04-01	161.798