Quarter	Millions of US Dollars
1977-04-01	8
1977-07-01	9
1977-10-01	10
1978-01-01	11
1978-04-01	73
1978-07-01	75
1978-10-01	74
1979-01-01	74
1979-04-01	74
1979-07-01	75
1979-10-01	75
1980-01-01	73
1980-04-01	74
1980-07-01	74
1980-10-01	73
1981-01-01	72
1981-04-01	72
1981-07-01	72
1981-10-01	73
1982-01-01	72
1982-04-01	62
1982-07-01	62
1982-10-01	62
1983-01-01	62
1983-04-01	62
1983-07-01	62
1983-10-01	62
1984-01-01	62
1984-04-01	62
1984-07-01	62
1984-10-01	62
1985-01-01	62
1985-04-01	72
1985-07-01	72
1985-10-01	72
1986-01-01	72
1986-04-01	72
1986-07-01	72
1986-10-01	72
1987-01-01	72
1987-04-01	72
1987-07-01	72
1987-10-01	72
1988-01-01	72
1988-04-01	10
1988-07-01	10
1988-10-01	10
1989-01-01	10
1989-04-01	10
1989-07-01	10
1989-10-01	10
1990-01-01	10
1990-04-01	10
1990-07-01	10
1990-10-01	10
1991-01-01	10
1991-04-01	10
1991-07-01	10
1991-10-01	10
1992-01-01	10
1992-04-01	10
1992-07-01	10
1992-10-01	10
1993-01-01	10
1993-04-01	10
1993-07-01	15
1993-10-01	25
1994-01-01	35
1994-04-01	45
1994-07-01	54
1994-10-01	254
1995-01-01	6017
1995-04-01	6038
1995-07-01	6047
1995-10-01	6063
1996-01-01	6098
1996-04-01	6099
1996-07-01	6141
1996-10-01	6257
1997-01-01	6239
1997-04-01	6852
1997-07-01	6872
1997-10-01	6799
1998-01-01	6800
1998-04-01	6725
1998-07-01	6681
1998-10-01	6338
1999-01-01	6316
1999-04-01	6316
1999-07-01	6316
1999-10-01	6316
2000-01-01	6294
2000-04-01	6294
2000-07-01	10044
2000-10-01	10044
2001-01-01	9571
2001-04-01	6429
2001-07-01	6429
2001-10-01	6429
2002-01-01	6429
2002-04-01	6282
2002-07-01	6282
2002-10-01	6279
2003-01-01	6279
2003-04-01	6277
2003-07-01	6277
2003-10-01	6277
2004-01-01	6277
2004-04-01	6277
2004-07-01	6277
2004-10-01	6275
2005-01-01	6462
2005-04-01	6462
2005-07-01	6462
2005-10-01	7112
2006-01-01	7112
2006-04-01	6372
2006-07-01	6372
2006-10-01	6372
2007-01-01	6372
2007-04-01	6372
2007-07-01	6372
2007-10-01	6372
2008-01-01	6372
2008-04-01	6372
2008-07-01	6372
2008-10-01	6372
2009-01-01	6340
2009-04-01	3432
2009-07-01	3301
2009-10-01	3301
2010-01-01	3170
2010-04-01	3099
2010-07-01	2969
2010-10-01	2969
2011-01-01	2969
2011-04-01	2969
2011-07-01	2319
2011-10-01	2319
2012-01-01	2137
2012-04-01	2137
2012-07-01	2137
2012-10-01	2069
2013-01-01	2069
2013-04-01	2069
2013-07-01	1488
2013-10-01	1488
2014-01-01	1294
2014-04-01	3294
2014-07-01	3294
2014-10-01	2912
2015-01-01	3657
2015-04-01	4397
2015-07-01	4397
2015-10-01	3747
2016-01-01	3747
2016-04-01	3747
2016-07-01	5747
2016-10-01	6497
2017-01-01	7497
2017-04-01	10813
2017-07-01	10813
2017-10-01	13613
2018-01-01	16613
2018-04-01	16613