Quarter	Billions of US Dollars
1996-10-01	19.749
1997-01-01	18.818
1997-04-01	18.674
1997-07-01	17.190
1997-10-01	17.287
1998-01-01	17.306
1998-04-01	18.109
1998-07-01	16.741
1998-10-01	16.448
1999-01-01	16.468
1999-04-01	14.564
1999-07-01	12.413
1999-10-01	13.108
2000-01-01	11.548
2000-04-01	10.205
2000-07-01	9.571
2000-10-01	9.032
2001-01-01	8.690
2001-04-01	8.921
2001-07-01	8.867
2001-10-01	9.097
2002-01-01	9.117
2002-04-01	9.536
2002-07-01	8.423
2002-10-01	8.692
2003-01-01	8.465
2003-04-01	9.015
2003-07-01	8.943
2003-10-01	9.511
2004-01-01	10.463
2004-04-01	11.219
2004-07-01	12.453
2004-10-01	14.392
2005-01-01	15.214
2005-04-01	16.614
2005-07-01	17.776
2005-10-01	19.155
2006-01-01	19.553
2006-04-01	18.384
2006-07-01	21.288
2006-10-01	24.286
2007-01-01	26.877
2007-04-01	31.771
2007-07-01	33.121
2007-10-01	35.060
2008-01-01	39.111
2008-04-01	38.220
2008-07-01	34.951
2008-10-01	34.884
2009-01-01	31.270
2009-04-01	38.811
2009-07-01	44.166
2009-10-01	42.971
2010-01-01	45.829
2010-04-01	47.686
2010-07-01	53.239
2010-10-01	53.165
2011-01-01	56.477
2011-04-01	62.954
2011-07-01	61.756
2011-10-01	64.011
2012-01-01	71.392
2012-04-01	73.477
2012-07-01	76.314
2012-10-01	81.509
2013-01-01	80.147
2013-04-01	80.002
2013-07-01	83.051
2013-10-01	85.024
2014-01-01	85.243
2014-04-01	92.536
2014-07-01	87.334
2014-10-01	76.994
2015-01-01	72.336
2015-04-01	74.161
2015-07-01	63.321
2015-10-01	64.120
2016-01-01	68.795
2016-04-01	73.794
2016-07-01	76.818
2016-10-01	75.402
2017-01-01	79.475
2017-04-01	77.133
2017-07-01	80.486
2017-10-01	80.502
2018-01-01	87.180