Quarter	Millions of US Dollars
1988-04-01	62466
1988-07-01	64084
1988-10-01	75575
1989-01-01	70366
1989-04-01	62741
1989-07-01	66314
1989-10-01	74305
1990-01-01	71818
1990-04-01	67005
1990-07-01	75051
1990-10-01	77254
1991-01-01	79485
1991-04-01	77695
1991-07-01	89664
1991-10-01	93783
1992-01-01	93777
1992-04-01	93584
1992-07-01	91555
1992-10-01	95572
1993-01-01	103164
1993-04-01	98232
1993-07-01	102304
1993-10-01	113108
1994-01-01	114093
1994-04-01	114757
1994-07-01	117374
1994-10-01	127107
1995-01-01	119777
1995-04-01	121141
1995-07-01	128133
1995-10-01	127735
1996-01-01	132708
1996-04-01	131302
1996-07-01	136307
1996-10-01	140147
1997-01-01	133876
1997-04-01	126946
1997-07-01	124929
1997-10-01	109147
1998-01-01	110232
1998-04-01	99066
1998-07-01	98532
1998-10-01	99163
1999-01-01	101117
1999-04-01	100802
1999-07-01	98330
1999-10-01	94805
2000-01-01	86511
2000-04-01	83822
2000-07-01	74229
2000-10-01	75202
2001-01-01	65875
2001-04-01	65987
2001-07-01	65666
2001-10-01	65898
2002-01-01	66436
2002-04-01	71037
2002-07-01	74991
2002-10-01	75030
2003-01-01	77982
2003-04-01	86458
2003-07-01	84820
2003-10-01	92027
2004-01-01	95208
2004-04-01	84634
2004-07-01	86495
2004-10-01	96341
2005-01-01	95937
2005-04-01	95153
2005-07-01	94785
2005-10-01	92108
2006-01-01	92797
2006-04-01	90518
2006-07-01	95823
2006-10-01	97471
2007-01-01	98189
2007-04-01	106707
2007-07-01	118630
2007-10-01	116713
2008-01-01	122371
2008-04-01	134382
2008-07-01	119865
2008-10-01	114597
2009-01-01	134970
2009-04-01	190995
2009-07-01	216593
2009-10-01	241278
2010-01-01	269272
2010-04-01	274873
2010-07-01	327075
2010-10-01	356768
2011-01-01	389525
2011-04-01	415255
2011-07-01	421846
2011-10-01	467912
2012-01-01	500977
2012-04-01	508530
2012-07-01	548672
2012-10-01	557932
2013-01-01	572834
2013-04-01	498355
2013-07-01	525616
2013-10-01	512932
2014-01-01	552673
2014-04-01	585436
2014-07-01	568856
2014-10-01	563003
2015-01-01	548347
2015-04-01	536853
2015-07-01	521635
2015-10-01	536993
2016-01-01	591927
2016-04-01	577064
2016-07-01	613173
2016-10-01	571665
2017-01-01	621840
2017-04-01	637619
2017-07-01	646881
2017-10-01	660953
2018-01-01	655217