Quarter	Billions of US Dollars
1987-01-01	2.694
1987-04-01	3.151
1987-07-01	3.308
1987-10-01	3.637
1988-01-01	3.873
1988-04-01	3.854
1988-07-01	4.073
1988-10-01	4.405
1989-01-01	4.277
1989-04-01	4.516
1989-07-01	4.667
1989-10-01	5.013
1990-01-01	4.739
1990-04-01	4.758
1990-07-01	5.250
1990-10-01	5.288
1991-01-01	4.790
1991-04-01	4.307
1991-07-01	5.209
1991-10-01	5.890
1992-01-01	5.750
1992-04-01	6.478
1992-07-01	6.549
1992-10-01	5.950
1993-01-01	5.689
1993-04-01	4.913
1993-07-01	5.344
1993-10-01	5.005
1994-01-01	5.053
1994-04-01	4.801
1994-07-01	4.581
1994-10-01	4.963
1995-01-01	5.658
1995-04-01	5.420
1995-07-01	5.392
1995-10-01	5.469
1996-01-01	5.777
1996-04-01	5.442
1996-07-01	5.140
1996-10-01	4.699
1997-01-01	5.528
1997-04-01	6.011
1997-07-01	6.395
1997-10-01	6.565
1998-01-01	7.147
1998-04-01	10.566
1998-07-01	12.815
1998-10-01	13.786
1999-01-01	17.934
1999-04-01	33.129
1999-07-01	43.947
1999-10-01	49.475
2000-01-01	50.999
2000-04-01	55.044
2000-07-01	57.469
2000-10-01	70.222
2001-01-01	72.938
2001-04-01	83.557
2001-07-01	94.921
2001-10-01	106.997
2002-01-01	110.291
2002-04-01	124.604
2002-07-01	129.022
2002-10-01	148.250
2003-01-01	169.627
2003-04-01	179.841
2003-07-01	187.042
2003-10-01	212.790
2004-01-01	211.157
2004-04-01	212.569
2004-07-01	207.549
2004-10-01	234.457
2005-01-01	220.505
2005-04-01	223.507
2005-07-01	222.970
2005-10-01	233.756
2006-01-01	240.545
2006-04-01	258.335
2006-07-01	266.278
2006-10-01	287.978
2007-01-01	299.854
2007-04-01	316.657
2007-07-01	333.411
2007-10-01	341.772
2008-01-01	365.918
2008-04-01	370.550
2008-07-01	352.374
2008-10-01	395.206
2009-01-01	393.936
2009-04-01	425.436
2009-07-01	470.109
2009-10-01	481.175
2010-01-01	448.085
2010-04-01	409.677
2010-07-01	450.878
2010-10-01	445.874
2011-01-01	471.845
2011-04-01	476.905
2011-07-01	442.235
2011-10-01	433.698
2012-01-01	420.324
2012-04-01	389.831
2012-07-01	393.211
2012-10-01	398.992
2013-01-01	386.241
2013-04-01	390.157
2013-07-01	408.584
2013-10-01	414.140
2014-01-01	416.855
2014-04-01	423.308
2014-07-01	387.829
2014-10-01	376.344
2015-01-01	344.495
2015-04-01	359.139