Quarter	Millions of US Dollars
1972-10-01	10
1973-01-01	14
1979-10-01	-10
1988-01-01	-14
1997-07-01	200
1998-04-01	250
2000-01-01	196
2000-07-01	225
2001-01-01	166
2001-04-01	400
2001-10-01	250
2002-04-01	300
2002-07-01	-200
2003-01-01	-215
2004-01-01	248
2004-04-01	125
2004-07-01	34
2004-10-01	186
2005-04-01	50
2005-10-01	250
2006-01-01	250
2007-01-01	350
2007-07-01	-225
2007-10-01	150
2008-04-01	350
2009-01-01	-260
2011-01-01	400
2011-04-01	-400
2012-07-01	-250
2014-07-01	800
2014-10-01	-187
2015-04-01	-300
2015-07-01	2000
2016-07-01	743
2017-04-01	-425
2017-07-01	869