Quarter	Millions of US Dollars
1978-01-01	20
1978-04-01	20
1978-07-01	20
1978-10-01	20
1979-01-01	20
1979-04-01	20
1979-07-01	20
1979-10-01	20
1980-01-01	20
1980-04-01	70
1980-07-01	82
1980-10-01	127
1981-01-01	124
1981-04-01	121
1981-07-01	122
1981-10-01	123
1982-01-01	121
1982-04-01	120
1982-07-01	119
1982-10-01	121
1983-01-01	120
1983-04-01	119
1983-07-01	118
1983-10-01	117
1984-01-01	119
1984-04-01	117
1984-07-01	115
1984-10-01	114
1985-01-01	94
1985-04-01	44
1985-07-01	48
1985-10-01	9
1986-01-01	10
1986-04-01	10
1986-07-01	11
1986-10-01	12
1987-01-01	12
1987-04-01	12
1987-07-01	12
1987-10-01	15
1988-01-01	14
1988-04-01	12
1988-07-01	12
1988-10-01	13
1989-01-01	11
1989-04-01	11
1989-07-01	12
1989-10-01	12
1990-01-01	13
1990-04-01	578
1990-07-01	579
1990-10-01	565
1991-01-01	565
1991-04-01	565
1991-07-01	565
1991-10-01	565
1992-01-01	565
1992-04-01	565
1992-07-01	565
1992-10-01	565
1993-01-01	565
1993-04-01	565
1993-07-01	565
1993-10-01	565
1994-01-01	615
1994-04-01	615
1994-07-01	615
1994-10-01	615
1995-01-01	615
1995-04-01	615
1995-07-01	615
1995-10-01	615
1996-01-01	615
1996-04-01	615
1996-07-01	615
1996-10-01	548
1997-01-01	498
1997-04-01	498
1997-07-01	511
1997-10-01	518
1998-01-01	506
1998-04-01	698
1998-07-01	698
1998-10-01	631
1999-01-01	631
1999-04-01	931
1999-07-01	931
1999-10-01	931
2000-01-01	931
2000-04-01	929
2000-07-01	1179
2000-10-01	1169
2001-01-01	1419
2001-04-01	1401
2001-07-01	1401
2001-10-01	1391
2002-01-01	1641
2002-04-01	1630
2002-07-01	1630
2002-10-01	1620
2003-01-01	2070
2003-04-01	1714
2003-07-01	1714
2003-10-01	1754
2004-01-01	1850
2004-04-01	1850
2004-07-01	1850
2004-10-01	1850
2005-01-01	1850
2005-04-01	1850
2005-07-01	1850
2005-10-01	1850
2006-01-01	1850
2006-04-01	1850
2006-07-01	1850
2006-10-01	1850
2007-01-01	1850
2007-04-01	1850
2007-07-01	1850
2007-10-01	1850
2008-01-01	1650
2008-04-01	1650
2008-07-01	1650
2008-10-01	1650
2009-01-01	1650
2009-04-01	1350
2009-07-01	1350
2009-10-01	1350
2010-01-01	1350
2010-04-01	1350
2010-07-01	1350
2010-10-01	1350
2011-01-01	1100
2011-04-01	1100
2011-07-01	1100
2011-10-01	1350
2012-01-01	1100
2012-04-01	1350
2012-07-01	1350
2012-10-01	2350
2013-01-01	2100
2013-04-01	3600
2013-07-01	4100
2013-10-01	5060
2014-01-01	4750
2014-04-01	5750
2014-07-01	5750
2014-10-01	5750
2015-01-01	6750
2015-04-01	6750
2015-07-01	6750
2015-10-01	6750
2016-01-01	6750
2016-04-01	7250
2016-07-01	7250
2016-10-01	7250
2017-01-01	7250
2017-04-01	7250
2017-07-01	7650
2017-10-01	7650
2018-01-01	7650
2018-04-01	7650