Quarter	Billions of US Dollars
1988-04-01	72.518
1988-07-01	71.097
1988-10-01	73.691
1989-01-01	68.406
1989-04-01	59.871
1989-07-01	61.550
1989-10-01	65.418
1990-01-01	65.764
1990-04-01	64.435
1990-07-01	67.880
1990-10-01	67.371
1991-01-01	70.134
1991-04-01	72.408
1991-07-01	82.719
1991-10-01	84.532
1992-01-01	85.681
1992-04-01	85.874
1992-07-01	86.144
1992-10-01	91.149
1993-01-01	98.814
1993-04-01	99.001
1993-07-01	100.012
1993-10-01	110.970
1994-01-01	112.399
1994-04-01	115.303
1994-07-01	118.294
1994-10-01	128.772
1995-01-01	122.529
1995-04-01	124.347
1995-07-01	131.399
1995-10-01	134.161
1996-01-01	138.499
1996-04-01	135.505
1996-07-01	139.080
1996-10-01	142.272
1997-01-01	137.610
1997-04-01	130.070
1997-07-01	125.611
1997-10-01	108.686
1998-01-01	110.508
1998-04-01	98.055
1998-07-01	96.466
1998-10-01	97.126
1999-01-01	95.994
1999-04-01	95.139
1999-07-01	93.342
1999-10-01	87.316
2000-01-01	80.829
2000-04-01	77.425
2000-07-01	66.775
2000-10-01	67.166
2001-01-01	57.849
2001-04-01	58.461
2001-07-01	58.186
2001-10-01	59.234
2002-01-01	58.704
2002-04-01	62.574
2002-07-01	62.402
2002-10-01	63.586
2003-01-01	64.378
2003-04-01	71.240
2003-07-01	68.269
2003-10-01	73.474
2004-01-01	75.083
2004-04-01	68.182
2004-07-01	69.911
2004-10-01	75.658
2005-01-01	73.962
2005-04-01	72.815
2005-07-01	71.745
2005-10-01	69.273
2006-01-01	68.315
2006-04-01	68.868
2006-07-01	71.096
2006-10-01	71.228
2007-01-01	71.954
2007-04-01	78.011
2007-07-01	86.055
2007-10-01	83.705
2008-01-01	88.681
2008-04-01	103.182
2008-07-01	87.454
2008-10-01	81.559
2009-01-01	91.824
2009-04-01	126.930
2009-07-01	154.022
2009-10-01	168.181
2010-01-01	189.530
2010-04-01	196.694
2010-07-01	239.214
2010-10-01	260.982
2011-01-01	285.345
2011-04-01	317.593
2011-07-01	323.455
2011-10-01	362.767
2012-01-01	386.040
2012-04-01	401.214
2012-07-01	435.325
2012-10-01	443.816
2013-01-01	452.347
2013-04-01	393.265
2013-07-01	422.221
2013-10-01	419.582
2014-01-01	450.520
2014-04-01	475.581
2014-07-01	462.736
2014-10-01	455.541
2015-01-01	444.219
2015-04-01	438.224
2015-07-01	429.384
2015-10-01	442.562
2016-01-01	489.908
2016-04-01	480.961
2016-07-01	514.697
2016-10-01	480.179
2017-01-01	525.599
2017-04-01	540.765
2017-07-01	550.706
2017-10-01	563.756
2018-01-01	560.818