Quarter	Millions of US Dollars
1988-04-01	55363
1988-07-01	57315
1988-10-01	61345
1989-01-01	65065
1989-04-01	65492
1989-07-01	71264
1989-10-01	70323
1990-01-01	65515
1990-04-01	70578
1990-07-01	76970
1990-10-01	68281
1991-01-01	72528
1991-04-01	70163
1991-07-01	69143
1991-10-01	61293
1992-01-01	64120
1992-04-01	62538
1992-07-01	59985
1992-10-01	56698
1993-01-01	57295
1993-04-01	52169
1993-07-01	51155
1993-10-01	53610
1994-01-01	59325
1994-04-01	60851
1994-07-01	62212
1994-10-01	66421
1995-01-01	64304
1995-04-01	61371
1995-07-01	69961
1995-10-01	71994
1996-01-01	78382
1996-04-01	80065
1996-07-01	80006
1996-10-01	84040
1997-01-01	82690
1997-04-01	82670
1997-07-01	80776
1997-10-01	75723
1998-01-01	77236
1998-04-01	77696
1998-07-01	76984
1998-10-01	86801
1999-01-01	91803
1999-04-01	101020
1999-07-01	106130
1999-10-01	110648
2000-01-01	105217
2000-04-01	107905
2000-07-01	95354
2000-10-01	95488
2001-01-01	86693
2001-04-01	89487
2001-07-01	87272
2001-10-01	94772
2002-01-01	102176
2002-04-01	108966
2002-07-01	109144
2002-10-01	113967
2003-01-01	124737
2003-04-01	145248
2003-07-01	154765
2003-10-01	177271
2004-01-01	190564
2004-04-01	173272
2004-07-01	187950
2004-10-01	214991
2005-01-01	216962
2005-04-01	215255
2005-07-01	214019
2005-10-01	212609
2006-01-01	212077
2006-04-01	231936
2006-07-01	234650
2006-10-01	262586
2007-01-01	271412
2007-04-01	303808
2007-07-01	396299
2007-10-01	449526
2008-01-01	459796
2008-04-01	468500
2008-07-01	402080
2008-10-01	320375
2009-01-01	287612
2009-04-01	333906
2009-07-01	348614
2009-10-01	346000
2010-01-01	334376
2010-04-01	301227
2010-07-01	322135
2010-10-01	344738
2011-01-01	347035
2011-04-01	352555
2011-07-01	320152
2011-10-01	328706
2012-01-01	343476
2012-04-01	336378
2012-07-01	330345
2012-10-01	322081
2013-01-01	316527
2013-04-01	283339
2013-07-01	275258
2013-10-01	256119
2014-01-01	273876
2014-04-01	278522
2014-07-01	251955
2014-10-01	233472
2015-01-01	208810
2015-04-01	213140
2015-07-01	188872
2015-10-01	188662
2016-01-01	205002
2016-04-01	191861
2016-07-01	194875
2016-10-01	182736
2017-01-01	194933
2017-04-01	205212
2017-07-01	207055
2017-10-01	188775
2018-01-01	182837