Quarter	Billions of US Dollars
1987-01-01	6.122
1987-04-01	6.429
1987-07-01	6.851
1987-10-01	7.427
1988-01-01	7.733
1988-04-01	8.660
1988-07-01	9.217
1988-10-01	10.031
1989-01-01	11.571
1989-04-01	12.409
1989-07-01	13.443
1989-10-01	14.622
1990-01-01	16.118
1990-04-01	16.967
1990-07-01	19.520
1990-10-01	19.631
1991-01-01	18.857
1991-04-01	18.759
1991-07-01	19.613
1991-10-01	18.699
1992-01-01	16.523
1992-04-01	17.433
1992-07-01	18.285
1992-10-01	16.269
1993-01-01	15.271
1993-04-01	14.659
1993-07-01	18.053
1993-10-01	18.321
1994-01-01	18.978
1994-04-01	18.232
1994-07-01	19.097
1994-10-01	19.222
1995-01-01	19.185
1995-04-01	18.308
1995-07-01	18.219
1995-10-01	18.360
1996-01-01	17.952
1996-04-01	17.588
1996-07-01	18.071
1996-10-01	17.554
1997-01-01	18.073
1997-04-01	17.978
1997-07-01	18.633
1997-10-01	19.345
1998-01-01	18.833
1998-04-01	20.455
1998-07-01	21.878
1998-10-01	21.407
1999-01-01	22.056
1999-04-01	24.354
1999-07-01	28.379
1999-10-01	27.057
2000-01-01	27.980
2000-04-01	27.795
2000-07-01	24.901
2000-10-01	27.534
2001-01-01	28.200
2001-04-01	27.456
2001-07-01	28.558
2001-10-01	27.919
2002-01-01	27.582
2002-04-01	30.739
2002-07-01	33.492
2002-10-01	35.547
2003-01-01	40.160
2003-04-01	40.605
2003-07-01	40.571
2003-10-01	45.591
2004-01-01	52.366
2004-04-01	54.894
2004-07-01	55.925
2004-10-01	65.112
2005-01-01	65.657
2005-04-01	70.295
2005-07-01	74.411
2005-10-01	71.864
2006-01-01	80.800
2006-04-01	84.322
2006-07-01	81.651
2006-10-01	91.455
2007-01-01	102.580
2007-04-01	114.847
2007-07-01	118.374
2007-10-01	124.257
2008-01-01	137.165
2008-04-01	159.988
2008-07-01	163.223
2008-10-01	148.681
2009-01-01	153.758
2009-04-01	177.236
2009-07-01	191.624
2009-10-01	189.750
2010-01-01	202.194
2010-04-01	186.249
2010-07-01	200.448
2010-10-01	197.128
2011-01-01	212.408
2011-04-01	226.877
2011-07-01	231.172
2011-10-01	220.454
2012-01-01	240.054
2012-04-01	240.467
2012-07-01	253.057
2012-10-01	245.342
2013-01-01	241.163
2013-04-01	248.844
2013-07-01	266.240
2013-10-01	257.799
2014-01-01	258.273
2014-04-01	254.025
2014-07-01	240.545
2014-10-01	230.283
2015-01-01	219.114
2015-04-01	228.714