Quarter	Billions of US Dollars
1990-01-01	8.064
1990-04-01	8.447
1990-07-01	8.731
1990-10-01	7.847
1991-01-01	7.241
1991-04-01	7.938
1991-07-01	8.458
1991-10-01	8.335
1992-01-01	8.784
1992-04-01	9.604
1992-07-01	9.938
1992-10-01	10.281
1993-01-01	10.648
1993-04-01	11.201
1993-07-01	11.837
1993-10-01	11.582
1994-01-01	12.018
1994-04-01	12.841
1994-07-01	13.573
1994-10-01	14.824
1995-01-01	14.282
1995-04-01	15.136
1995-07-01	15.255
1995-10-01	14.638
1996-01-01	15.463
1996-04-01	15.979
1996-07-01	16.544
1996-10-01	15.179
1997-01-01	14.994
1997-04-01	14.841
1997-07-01	13.321
1997-10-01	12.418
1998-01-01	12.040
1998-04-01	10.843
1998-07-01	10.763
1998-10-01	11.942
1999-01-01	12.476
1999-04-01	12.737
1999-07-01	12.719
1999-10-01	12.770
2000-01-01	11.388
2000-04-01	11.000
2000-07-01	9.762
2000-10-01	11.013
2001-01-01	9.533
2001-04-01	10.040
2001-07-01	10.296
2001-10-01	10.804
2002-01-01	10.888
2002-04-01	12.803
2002-07-01	12.544
2002-10-01	14.505
2003-01-01	15.377
2003-04-01	14.869
2003-07-01	15.658
2003-10-01	17.708
2004-01-01	18.040
2004-04-01	15.659
2004-07-01	17.653
2004-10-01	19.386
2005-01-01	17.568
2005-04-01	17.842
2005-07-01	18.007
2005-10-01	18.298
2006-01-01	15.412
2006-04-01	15.658
2006-07-01	17.413
2006-10-01	16.914
2007-01-01	17.400
2007-04-01	19.218
2007-07-01	19.266
2007-10-01	20.178
2008-01-01	21.046
2008-04-01	20.384
2008-07-01	16.614
2008-10-01	15.039
2009-01-01	15.452
2009-04-01	19.267
2009-07-01	20.705
2009-10-01	22.757
2010-01-01	24.220
2010-04-01	25.446
2010-07-01	30.006
2010-10-01	34.916
2011-01-01	38.091
2011-04-01	45.893
2011-07-01	44.851
2011-10-01	41.702
2012-01-01	45.854
2012-04-01	46.954
2012-07-01	52.195
2012-10-01	54.203
2013-01-01	56.633
2013-04-01	46.188
2013-07-01	49.809
2013-10-01	50.237
2014-01-01	53.110
2014-04-01	52.696
2014-07-01	47.496
2014-10-01	48.580
2015-01-01	46.790