Quarter	Millions of US Dollars
1978-01-01	0
1978-04-01	0
1978-07-01	0
1978-10-01	0
1979-01-01	0
1979-04-01	0
1979-07-01	0
1979-10-01	0
1980-01-01	0
1980-04-01	0
1980-07-01	0
1980-10-01	0
1981-01-01	0
1981-04-01	0
1981-07-01	0
1981-10-01	0
1982-01-01	21
1982-04-01	20
1982-07-01	20
1982-10-01	21
1983-01-01	30
1983-04-01	110
1983-07-01	130
1983-10-01	130
1984-01-01	100
1984-04-01	20
1984-07-01	0
1984-10-01	4
1985-01-01	4
1985-04-01	44
1985-07-01	92
1985-10-01	95
1986-01-01	106
1986-04-01	55
1986-07-01	0
1986-10-01	0
1987-01-01	0
1987-04-01	68
1987-07-01	68
1987-10-01	82
1988-01-01	81
1988-04-01	75
1988-07-01	74
1988-10-01	80
1989-01-01	220
1989-04-01	445
1989-07-01	517
1989-10-01	515
1990-01-01	435
1990-04-01	141
1990-07-01	251
1990-10-01	328
1991-01-01	238
1991-04-01	241
1991-07-01	75
1991-10-01	0
1992-01-01	30
1992-04-01	32
1992-07-01	175
1992-10-01	156
1993-01-01	211
1993-04-01	277
1993-07-01	242
1993-10-01	254
1994-01-01	335
1994-04-01	272
1994-07-01	437
1994-10-01	453
1995-01-01	498
1995-04-01	496
1995-07-01	514
1995-10-01	514
1996-01-01	1011
1996-04-01	1006
1996-07-01	1042
1996-10-01	926
1997-01-01	815
1997-04-01	831
1997-07-01	710
1997-10-01	811
1998-01-01	864
1998-04-01	1083
1998-07-01	1553
1998-10-01	1370
1999-01-01	1195
1999-04-01	1149
1999-07-01	825
1999-10-01	1052
2000-01-01	1466
2000-04-01	1934
2000-07-01	2625
2000-10-01	3239
2001-01-01	2836
2001-04-01	3132
2001-07-01	2288
2001-10-01	1472
2002-01-01	1093
2002-04-01	1150
2002-07-01	2274
2002-10-01	2550
2003-01-01	3358
2003-04-01	3190
2003-07-01	2921
2003-10-01	2569
2004-01-01	1430
2004-04-01	1092
2004-07-01	1350
2004-10-01	1621
2005-01-01	1750
2005-04-01	2408
2005-07-01	1362
2005-10-01	1974
2006-01-01	2111
2006-04-01	3745
2006-07-01	4262
2006-10-01	3155
2007-01-01	2497
2007-04-01	1577
2007-07-01	1211
2007-10-01	1408
2008-01-01	1527
2008-04-01	1186
2008-07-01	1411
2008-10-01	1171
2009-01-01	1436
2009-04-01	1328
2009-07-01	1070
2009-10-01	1056
2010-01-01	606
2010-04-01	696
2010-07-01	1124
2010-10-01	861
2011-01-01	856
2011-04-01	410
2011-07-01	472
2011-10-01	722
2012-01-01	1194
2012-04-01	1587
2012-07-01	1131
2012-10-01	1322
2013-01-01	827
2013-04-01	465
2013-07-01	1090
2013-10-01	725
2014-01-01	925
2014-04-01	1674
2014-07-01	1742
2014-10-01	2041
2015-01-01	1990
2015-04-01	1306
2015-07-01	936
2015-10-01	1120
2016-01-01	1020
2016-04-01	1620
2016-07-01	3267
2016-10-01	5039
2017-01-01	5581
2017-04-01	5060
2017-07-01	4625
2017-10-01	2727
2018-01-01	2522
2018-04-01	3540