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	14765
1997-01-01	15056
1997-04-01	14187
1997-07-01	17245
1997-10-01	20205
1998-01-01	18771
1998-04-01	18720
1998-07-01	20179
1998-10-01	19267
1999-01-01	16782
1999-04-01	13830
1999-07-01	13039
1999-10-01	15193
2000-01-01	13684
2000-04-01	14846
2000-07-01	15162
2000-10-01	17679
2001-01-01	17332
2001-04-01	16170
2001-07-01	15933
2001-10-01	15109
2002-01-01	15532
2002-04-01	16977
2002-07-01	16769
2002-10-01	18093
2003-01-01	17543
2003-04-01	18842
2003-07-01	20841
2003-10-01	25298
2004-01-01	27332
2004-04-01	28978
2004-07-01	29647
2004-10-01	34938
2005-01-01	34231
2005-04-01	36882
2005-07-01	34412
2005-10-01	35921
2006-01-01	38363
2006-04-01	40512
2006-07-01	37417
2006-10-01	38905
2007-01-01	38140
2007-04-01	38285
2007-07-01	35932
2007-10-01	35188
2008-01-01	37569
2008-04-01	38998
2008-07-01	36318
2008-10-01	32398
2009-01-01	28167
2009-04-01	29120
2009-07-01	28910
2009-10-01	30783
2010-01-01	30488
2010-04-01	31682
2010-07-01	31270
2010-10-01	36054
2011-01-01	36040
2011-04-01	38517
2011-07-01	37689
2011-10-01	38687
2012-01-01	39029
2012-04-01	40565
2012-07-01	41452
2012-10-01	43143
2013-01-01	41760
2013-04-01	41870
2013-07-01	41991
2013-10-01	42325
2014-01-01	41031
2014-04-01	44951
2014-07-01	43683
2014-10-01	46547
2015-01-01	47547
2015-04-01	48089
2015-07-01	47163
2015-10-01	46342
2016-01-01	46647
2016-04-01	49002
2016-07-01	49077
2016-10-01	46538
2017-01-01	51543
2017-04-01	52523
2017-07-01	53773
2017-10-01	55429
2018-01-01	57372