Quarter	Billions of US Dollars
1987-01-01	9.692
1987-04-01	11.521
1987-07-01	13.297
1987-10-01	15.487
1988-01-01	16.304
1988-04-01	16.297
1988-07-01	17.143
1988-10-01	18.558
1989-01-01	21.151
1989-04-01	23.785
1989-07-01	25.308
1989-10-01	26.984
1990-01-01	29.118
1990-04-01	30.042
1990-07-01	34.687
1990-10-01	34.968
1991-01-01	33.777
1991-04-01	33.176
1991-07-01	33.749
1991-10-01	34.601
1992-01-01	33.310
1992-04-01	34.282
1992-07-01	32.798
1992-10-01	31.881
1993-01-01	31.029
1993-04-01	30.721
1993-07-01	28.875
1993-10-01	29.237
1994-01-01	28.021
1994-04-01	27.665
1994-07-01	26.974
1994-10-01	27.369
1995-01-01	28.504
1995-04-01	28.694
1995-07-01	24.013
1995-10-01	23.506
1996-01-01	23.252
1996-04-01	23.298
1996-07-01	23.489
1996-10-01	22.490
1997-01-01	21.986
1997-04-01	22.382
1997-07-01	21.404
1997-10-01	19.980
1998-01-01	20.169
1998-04-01	19.627
1998-07-01	20.834
1998-10-01	21.259
1999-01-01	21.393
1999-04-01	21.465
1999-07-01	22.108
1999-10-01	21.522
2000-01-01	22.288
2000-04-01	23.292
2000-07-01	23.794
2000-10-01	24.338
2001-01-01	22.950
2001-04-01	24.139
2001-07-01	24.505
2001-10-01	25.506
2002-01-01	25.486
2002-04-01	27.556
2002-07-01	27.752
2002-10-01	28.386
2003-01-01	29.483
2003-04-01	30.902
2003-07-01	33.274
2003-10-01	34.368
2004-01-01	34.488
2004-04-01	35.370
2004-07-01	37.459
2004-10-01	40.494
2005-01-01	42.663
2005-04-01	42.298
2005-07-01	46.071
2005-10-01	46.651
2006-01-01	50.991
2006-04-01	52.414
2006-07-01	55.271
2006-10-01	54.564
2007-01-01	56.859
2007-04-01	57.681
2007-07-01	59.788
2007-10-01	62.009
2008-01-01	66.539
2008-04-01	65.691
2008-07-01	62.947
2008-10-01	66.014
2009-01-01	63.002
2009-04-01	64.255
2009-07-01	67.980
2009-10-01	64.288
2010-01-01	67.549
2010-04-01	63.588
2010-07-01	70.839
2010-10-01	72.089
2011-01-01	72.880
2011-04-01	72.829
2011-07-01	74.969
2011-10-01	75.201
2012-01-01	79.967
2012-04-01	78.670
2012-07-01	86.399
2012-10-01	86.307
2013-01-01	92.066
2013-04-01	91.794
2013-07-01	103.621
2013-10-01	106.242
2014-01-01	115.622
2014-04-01	125.520
2014-07-01	133.000
2014-10-01	131.726
2015-01-01	141.154
2015-04-01	140.976