Quarter	Millions of US Dollars
1987-04-01	2490
1987-07-01	2692
1987-10-01	903
1988-01-01	1294
1988-04-01	2039
1988-07-01	3357
1988-10-01	5461
1989-01-01	5246
1989-04-01	14106
1989-07-01	14866
1989-10-01	13552
1990-01-01	19528
1990-04-01	17390
1990-07-01	16726
1990-10-01	10944
1991-01-01	9790
1991-04-01	13693
1991-07-01	11976
1991-10-01	11885
1992-01-01	10533
1992-04-01	13673
1992-07-01	16399
1992-10-01	18281
1993-01-01	18296
1993-04-01	20512
1993-07-01	15082
1993-10-01	13622
1994-01-01	12578
1994-04-01	10985
1994-07-01	14018
1994-10-01	16757
1995-01-01	16097
1995-04-01	17300
1995-07-01	15774
1995-10-01	17596
1996-01-01	15904
1996-04-01	15394
1996-07-01	14546
1996-10-01	13502
1997-01-01	12464
1997-04-01	11854
1997-07-01	14937
1997-10-01	18105
1998-01-01	16424
1998-04-01	16491
1998-07-01	17600
1998-10-01	16403
1999-01-01	13705
1999-04-01	10902
1999-07-01	9579
1999-10-01	12075
2000-01-01	10743
2000-04-01	12122
2000-07-01	12860
2000-10-01	14910
2001-01-01	14340
2001-04-01	13096
2001-07-01	11679
2001-10-01	9330
2002-01-01	8782
2002-04-01	8708
2002-07-01	6948
2002-10-01	7237
2003-01-01	6160
2003-04-01	6580
2003-07-01	7125
2003-10-01	9377
2004-01-01	9103
2004-04-01	10225
2004-07-01	10534
2004-10-01	12649
2005-01-01	11036
2005-04-01	12257
2005-07-01	10785
2005-10-01	11220
2006-01-01	13020
2006-04-01	13549
2006-07-01	11366
2006-10-01	10488
2007-01-01	9679
2007-04-01	9961
2007-07-01	7782
2007-10-01	6907
2008-01-01	6849
2008-04-01	6347
2008-07-01	6220
2008-10-01	5111
2009-01-01	4007
2009-04-01	4099
2009-07-01	3732
2009-10-01	5375
2010-01-01	6447
2010-04-01	7834
2010-07-01	6377
2010-10-01	8068
2011-01-01	7771
2011-04-01	8392
2011-07-01	8426
2011-10-01	8963
2012-01-01	8468
2012-04-01	8907
2012-07-01	8185
2012-10-01	7956
2013-01-01	6973
2013-04-01	7919
2013-07-01	7740
2013-10-01	7790
2014-01-01	6683
2014-04-01	7302
2014-07-01	6433
2014-10-01	6322
2015-01-01	5887
2015-04-01	6446
2015-07-01	7198
2015-10-01	7227
2016-01-01	6891
2016-04-01	9783
2016-07-01	8602
2016-10-01	9233
2017-01-01	10415
2017-04-01	10874
2017-07-01	12590
2017-10-01	14041
2018-01-01	13096