Quarter	Millions of US Dollars
1977-04-01	0
1977-07-01	0
1977-10-01	0
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	50
1981-07-01	50
1981-10-01	50
1982-01-01	50
1982-04-01	0
1982-07-01	0
1982-10-01	0
1983-01-01	0
1983-04-01	0
1983-07-01	0
1983-10-01	0
1984-01-01	0
1984-04-01	30
1984-07-01	30
1984-10-01	30
1985-01-01	30
1985-04-01	0
1985-07-01	0
1985-10-01	0
1986-01-01	0
1986-04-01	0
1986-07-01	0
1986-10-01	31
1987-01-01	33
1987-04-01	33
1987-07-01	33
1987-10-01	30
1988-01-01	30
1988-04-01	30
1988-07-01	30
1988-10-01	100
1989-01-01	100
1989-04-01	100
1989-07-01	103
1989-10-01	763
1990-01-01	1464
1990-04-01	1569
1990-07-01	1645
1990-10-01	900
1991-01-01	146
1991-04-01	122
1991-07-01	297
1991-10-01	358
1992-01-01	417
1992-04-01	713
1992-07-01	704
1992-10-01	579
1993-01-01	620
1993-04-01	409
1993-07-01	313
1993-10-01	384
1994-01-01	363
1994-04-01	354
1994-07-01	510
1994-10-01	462
1995-01-01	557
1995-04-01	461
1995-07-01	635
1995-10-01	1649
1996-01-01	980
1996-04-01	946
1996-07-01	435
1996-10-01	220
1997-01-01	1207
1997-04-01	1343
1997-07-01	1549
1997-10-01	1393
1998-01-01	2013
1998-04-01	2611
1998-07-01	4288
1998-10-01	4489
1999-01-01	3189
1999-04-01	2718
1999-07-01	1552
1999-10-01	2510
2000-01-01	3582
2000-04-01	2399
2000-07-01	2001
2000-10-01	2556
2001-01-01	1803
2001-04-01	1880
2001-07-01	2965
2001-10-01	4172
2002-01-01	2933
2002-04-01	2480
2002-07-01	3402
2002-10-01	4908
2003-01-01	6859
2003-04-01	7474
2003-07-01	9241
2003-10-01	6808
2004-01-01	4544
2004-04-01	7441
2004-07-01	5972
2004-10-01	5610
2005-01-01	4292
2005-04-01	1074
2005-07-01	4014
2005-10-01	4721
2006-01-01	6419
2006-04-01	10136
2006-07-01	9778
2006-10-01	11430
2007-01-01	9834
2007-04-01	8739
2007-07-01	7336
2007-10-01	7362
2008-01-01	7082
2008-04-01	9368
2008-07-01	6857
2008-10-01	9823
2009-01-01	8208
2009-04-01	15562
2009-07-01	21269
2009-10-01	22819
2010-01-01	24709
2010-04-01	21686
2010-07-01	22815
2010-10-01	20420
2011-01-01	23900
2011-04-01	18123
2011-07-01	21044
2011-10-01	20860
2012-01-01	15837
2012-04-01	17054
2012-07-01	11696
2012-10-01	16657
2013-01-01	16154
2013-04-01	19494
2013-07-01	21869
2013-10-01	30199
2014-01-01	28261
2014-04-01	16363
2014-07-01	15014
2014-10-01	7678
2015-01-01	4400
2015-04-01	6159
2015-07-01	4299
2015-10-01	9961
2016-01-01	11346
2016-04-01	10548
2016-07-01	10352
2016-10-01	5932
2017-01-01	6372
2017-04-01	10349
2017-07-01	10309
2017-10-01	7295
2018-01-01	7549
2018-04-01	9335