Quarter	Millions of US Dollars
1996-10-01	200
1997-01-01	200
1997-04-01	200
1997-07-01	200
1997-10-01	550
1998-01-01	550
1998-04-01	550
1998-07-01	550
1998-10-01	550
1999-01-01	550
1999-04-01	550
1999-07-01	550
1999-10-01	650
2000-01-01	650
2000-04-01	1000
2000-07-01	1000
2000-10-01	1000
2001-01-01	1000
2001-04-01	1000
2001-07-01	1000
2001-10-01	1000
2002-01-01	1000
2002-04-01	1000
2002-07-01	1000
2002-10-01	650
2003-01-01	650
2003-04-01	650
2003-07-01	650
2003-10-01	650
2004-01-01	650
2004-04-01	650
2004-07-01	650
2004-10-01	350
2005-01-01	350
2005-04-01	350
2005-07-01	350
2005-10-01	350
2006-01-01	350
2006-04-01	350
2006-07-01	350
2006-10-01	350
2007-01-01	350
2014-10-01	3205
2015-01-01	3054
2015-04-01	3148
2015-07-01	8513
2015-10-01	8724
2016-01-01	12851
2016-04-01	9049
2016-07-01	9173
2016-10-01	9235
2017-01-01	9338
2017-04-01	9387
2017-07-01	9342
2017-10-01	9380
2018-01-01	9418
2018-04-01	9478