Quarter	Millions of US Dollars
1988-04-01	48986
1988-07-01	50779
1988-10-01	58843
1989-01-01	54831
1989-04-01	52398
1989-07-01	53087
1989-10-01	56834
1990-01-01	53640
1990-04-01	58102
1990-07-01	61932
1990-10-01	61136
1991-01-01	61569
1991-04-01	64744
1991-07-01	71994
1991-10-01	73767
1992-01-01	72947
1992-04-01	77350
1992-07-01	75034
1992-10-01	76386
1993-01-01	85591
1993-04-01	82796
1993-07-01	88041
1993-10-01	97708
1994-01-01	97026
1994-04-01	98087
1994-07-01	97666
1994-10-01	106098
1995-01-01	103404
1995-04-01	106212
1995-07-01	110872
1995-10-01	113182
1996-01-01	115205
1996-04-01	117226
1996-07-01	119629
1996-10-01	123239
1997-01-01	117713
1997-04-01	115189
1997-07-01	111022
1997-10-01	97075
1998-01-01	97592
1998-04-01	90197
1998-07-01	87621
1998-10-01	89878
1999-01-01	89862
1999-04-01	90909
1999-07-01	87184
1999-10-01	82898
2000-01-01	77422
2000-04-01	77075
2000-07-01	67614
2000-10-01	70625
2001-01-01	61565
2001-04-01	62093
2001-07-01	60437
2001-10-01	60255
2002-01-01	59812
2002-04-01	66203
2002-07-01	67093
2002-10-01	68053
2003-01-01	72116
2003-04-01	81586
2003-07-01	78365
2003-10-01	85247
2004-01-01	89089
2004-04-01	80253
2004-07-01	81631
2004-10-01	90575
2005-01-01	90974
2005-04-01	90292
2005-07-01	88624
2005-10-01	86687
2006-01-01	88152
2006-04-01	86644
2006-07-01	90312
2006-10-01	90675
2007-01-01	92876
2007-04-01	101287
2007-07-01	108683
2007-10-01	107090
2008-01-01	113641
2008-04-01	125528
2008-07-01	110307
2008-10-01	105430
2009-01-01	123260
2009-04-01	167513
2009-07-01	196530
2009-10-01	216787
2010-01-01	248074
2010-04-01	255840
2010-07-01	302463
2010-10-01	328121
2011-01-01	361512
2011-04-01	385062
2011-07-01	398190
2011-10-01	442544
2012-01-01	471396
2012-04-01	480850
2012-07-01	517628
2012-10-01	521632
2013-01-01	544272
2013-04-01	479981
2013-07-01	504462
2013-10-01	494713
2014-01-01	542714
2014-04-01	569072
2014-07-01	548016
2014-10-01	538776
2015-01-01	526854
2015-04-01	518474
2015-07-01	499014
2015-10-01	517145
2016-01-01	570780
2016-04-01	559903
2016-07-01	595372
2016-10-01	556012
2017-01-01	605574
2017-04-01	624067
2017-07-01	632068
2017-10-01	647081
2018-01-01	639749