Quarter	Millions of US Dollars
1987-01-01	74
1987-04-01	73
1987-07-01	72
1987-10-01	84
1988-01-01	81
1988-04-01	73
1988-07-01	71
1988-10-01	75
1989-01-01	70
1989-04-01	68
1989-07-01	71
1989-10-01	79
1990-01-01	79
1990-04-01	80
1990-07-01	85
1990-10-01	89
1991-01-01	78
1991-04-01	73
1991-07-01	80
1991-10-01	88
1992-01-01	81
1992-04-01	87
1992-07-01	94
1992-10-01	83
1993-01-01	83
1993-04-01	79
1993-07-01	82
1993-10-01	77
1994-01-01	80
1994-04-01	84
1994-07-01	87
1994-10-01	86
1995-01-01	97
1995-04-01	110
1995-07-01	107
1995-10-01	106
1996-01-01	103
1996-04-01	125
1996-07-01	98
1996-10-01	96
1997-01-01	15
1997-04-01	21
1997-07-01	28
1997-10-01	28
1998-01-01	27
1998-04-01	27
1998-07-01	29
1998-10-01	29
1999-01-01	48
1999-04-01	45
1999-07-01	46
1999-10-01	44
2000-01-01	42
2000-04-01	39
2000-07-01	36
2000-10-01	38
2001-01-01	33
2001-04-01	30
2001-07-01	33
2001-10-01	32
2002-01-01	29
2002-04-01	34
2002-07-01	34
2002-10-01	38
2003-01-01	40
2003-04-01	40
2003-07-01	41
2003-10-01	270
2004-01-01	272
2004-04-01	251
2004-07-01	260
2004-10-01	360
2005-01-01	355
2005-04-01	345
2005-07-01	345
2005-10-01	333
2006-01-01	326
2006-04-01	340
2006-07-01	6801
2006-10-01	6765
2007-01-01	6841
2007-04-01	6937
2007-07-01	7283
2007-10-01	7562
2008-01-01	20987
2008-04-01	21742
2008-07-01	29385
2008-10-01	28044
2009-01-01	29560
2009-04-01	24362
2009-07-01	30774
2009-10-01	23029
2010-01-01	26061
2010-04-01	20195
2010-07-01	25808
2010-10-01	22668
2011-01-01	17259
2011-04-01	17518
2011-07-01	19110
2011-10-01	25412
2012-01-01	27911
2012-04-01	23410
2012-07-01	24041
2012-10-01	31475
2013-01-01	24911
2013-04-01	28539
2013-07-01	31775
2013-10-01	17741
2014-01-01	18484
2014-04-01	28272
2014-07-01	25887
2014-10-01	14169
2015-01-01	12556
2015-04-01	15838
2015-07-01	21722
2015-10-01	13535
2016-01-01	13286
2016-04-01	12956
2016-07-01	7329
2016-10-01	8297
2017-01-01	7021
2017-04-01	10509
2017-07-01	10768
2017-10-01	7976
2018-01-01	8191
2018-04-01	12852