Quarter	Billions of US Dollars
1987-01-01	1.899
1987-04-01	2.039
1987-07-01	2.571
1987-10-01	2.909
1988-01-01	4.150
1988-04-01	3.837
1988-07-01	4.429
1988-10-01	5.035
1989-01-01	5.504
1989-04-01	5.623
1989-07-01	6.110
1989-10-01	6.700
1990-01-01	6.978
1990-04-01	7.403
1990-07-01	8.408
1990-10-01	10.632
1991-01-01	8.399
1991-04-01	8.782
1991-07-01	9.650
1991-10-01	10.564
1992-01-01	10.366
1992-04-01	11.372
1992-07-01	11.930
1992-10-01	11.851
1993-01-01	11.107
1993-04-01	10.876
1993-07-01	12.571
1993-10-01	13.149
1994-01-01	14.282
1994-04-01	15.504
1994-07-01	16.264
1994-10-01	16.912
1995-01-01	18.252
1995-04-01	19.954
1995-07-01	21.730
1995-10-01	21.486
1996-01-01	22.648
1996-04-01	24.690
1996-07-01	25.598
1996-10-01	27.974
1997-01-01	27.517
1997-04-01	28.135
1997-07-01	28.793
1997-10-01	28.898
1998-01-01	32.451
1998-04-01	31.860
1998-07-01	29.924
1998-10-01	32.077
1999-01-01	30.697
1999-04-01	31.281
1999-07-01	34.730
1999-10-01	34.819
2000-01-01	33.079
2000-04-01	36.675
2000-07-01	37.602
2000-10-01	44.274
2001-01-01	46.666
2001-04-01	48.727
2001-07-01	53.579
2001-10-01	54.853
2002-01-01	55.690
2002-04-01	65.710
2002-07-01	56.351
2002-10-01	58.400
2003-01-01	56.085
2003-04-01	57.508
2003-07-01	62.004
2003-10-01	78.466
2004-01-01	73.170
2004-04-01	75.497
2004-07-01	75.873
2004-10-01	86.403
2005-01-01	90.353
2005-04-01	92.148
2005-07-01	97.263
2005-10-01	102.074
2006-01-01	115.819
2006-04-01	129.046
2006-07-01	131.082
2006-10-01	144.915
2007-01-01	149.712
2007-04-01	162.374
2007-07-01	174.828
2007-10-01	180.845
2008-01-01	182.742
2008-04-01	195.513
2008-07-01	185.713
2008-10-01	171.159
2009-01-01	165.072
2009-04-01	170.451
2009-07-01	168.639
2009-10-01	165.745
2010-01-01	161.238
2010-04-01	145.480
2010-07-01	154.837
2010-10-01	147.602
2011-01-01	149.234
2011-04-01	150.702
2011-07-01	140.988
2011-10-01	135.941
2012-01-01	145.287
2012-04-01	143.446
2012-07-01	143.242
2012-10-01	145.780
2013-01-01	141.600
2013-04-01	138.460
2013-07-01	141.502
2013-10-01	143.050
2014-01-01	144.453
2014-04-01	143.160
2014-07-01	135.926
2014-10-01	130.863
2015-01-01	125.770
2015-04-01	123.148