Quarter	Billions of US Dollars
1997-04-01	0.13321
1997-07-01	0.12932
1997-10-01	0.06979
1998-01-01	0.08554
1998-04-01	0.09636
1998-07-01	0.09511
1998-10-01	0.10988
1999-01-01	0.10782
1999-04-01	0.10219
1999-07-01	0.09725
1999-10-01	0.10395
2000-01-01	0.10696
2000-04-01	0.10610
2000-07-01	0.10610
2000-10-01	0.09355
2001-01-01	0.10041
2001-04-01	0.10274
2001-07-01	0.10179
2001-10-01	0.26136
2002-01-01	0.24761
2002-04-01	0.17481
2002-07-01	0.17104
2002-10-01	0.17704
2003-01-01	0.16738
2003-04-01	0.23468
2003-07-01	0.35475
2003-10-01	0.37146
2004-01-01	0.40496
2004-04-01	0.42780
2004-07-01	0.40747
2004-10-01	0.42926
2005-01-01	0.43754
2005-04-01	0.39431
2005-07-01	0.59593
2005-10-01	0.63308
2006-01-01	0.76901
2006-04-01	0.76830
2006-07-01	0.78116
2006-10-01	0.80655
2007-01-01	0.77437
2007-04-01	0.75679
2007-07-01	0.70636
2007-10-01	0.66428
2008-01-01	0.62931
2008-04-01	0.58490
2008-07-01	0.46136
2008-10-01	0.44213
2009-01-01	0.34079
2009-04-01	0.68410
2009-07-01	0.73973
2009-10-01	0.77319
2010-01-01	1.13576
2010-04-01	1.15425
2010-07-01	1.16542
2010-10-01	1.25028
2011-01-01	1.26760
2011-04-01	1.31046
2011-07-01	1.19062
2011-10-01	1.08662
2012-01-01	1.11114
2012-04-01	0.97691
2012-07-01	1.00679
2012-10-01	0.68295
2013-01-01	0.57948
2013-04-01	0.61423
2013-07-01	0.57461
2013-10-01	0.58304
2014-01-01	0.54695
2014-04-01	0.57344
2014-07-01	0.58581
2014-10-01	0.56346
2015-01-01	0.55828
2015-04-01	0.50023