Quarter	Millions of US Dollars
1987-07-01	38
1987-10-01	22
1988-01-01	94
1988-04-01	65
1988-07-01	57
1989-10-01	76
1990-01-01	131
1990-04-01	107
1990-07-01	446
1990-10-01	390
1991-01-01	701
1991-04-01	809
1991-07-01	947
1991-10-01	1024
1992-01-01	1015
1992-04-01	1254
1992-07-01	775
1992-10-01	478
1993-01-01	200
1993-04-01	195
1993-10-01	73
1994-01-01	221
1994-04-01	560
1994-07-01	405
1994-10-01	717
1995-01-01	298
1995-04-01	350
1995-07-01	592
1995-10-01	701
1996-01-01	779
1996-04-01	656
1996-07-01	404
1996-10-01	510
1997-01-01	398
1997-04-01	487
1997-07-01	559
1997-10-01	414
1998-01-01	440
1998-04-01	468
1998-07-01	422
1998-10-01	315
1999-01-01	231
1999-04-01	186
1999-07-01	157
1999-10-01	174
2000-01-01	166
2000-04-01	188
2000-07-01	203
2000-10-01	175
2001-01-01	197
2001-04-01	256
2001-07-01	264
2001-10-01	226
2002-01-01	154
2002-04-01	284
2002-07-01	267
2002-10-01	274
2003-01-01	277
2003-04-01	277
2003-07-01	471
2003-10-01	496
2004-01-01	499
2004-04-01	699
2004-07-01	710
2004-10-01	700
2005-01-01	685
2005-04-01	692
2005-07-01	691
2005-10-01	675
2006-01-01	668
2006-04-01	636
2006-07-01	640
2006-10-01	637
2007-01-01	635
2007-04-01	626
2007-07-01	630
2007-10-01	633
2008-01-01	632
2008-04-01	726
2008-07-01	724
2008-10-01	726
2009-01-01	722
2009-04-01	724
2009-07-01	723
2009-10-01	1320
2010-01-01	1315
2010-04-01	1313
2010-07-01	1314
2010-10-01	1314
2011-01-01	1315
2011-04-01	1315
2011-07-01	1114
2011-10-01	1182
2012-01-01	1183
2012-04-01	1407
2012-07-01	1407
2012-10-01	2058
2013-01-01	2057
2013-04-01	2057
2013-07-01	2058
2013-10-01	2058
2014-01-01	2358
2014-04-01	2358
2014-07-01	3404
2014-10-01	3403
2015-01-01	3402
2015-04-01	3402
2015-07-01	3402
2015-10-01	3402
2016-01-01	3402
2016-04-01	3402
2016-07-01	3402
2016-10-01	3401
2017-01-01	3952
2017-04-01	3952
2017-07-01	3953
2017-10-01	4353
2018-01-01	4353
2018-04-01	4998