Quarter	Millions of US Dollars
1972-10-01	20
1973-04-01	22
1975-10-01	30
1977-01-01	30
1977-04-01	51
1978-01-01	43
1978-07-01	25
1980-10-01	-20
1981-10-01	-30
1984-01-01	-30
1984-07-01	-17
1985-04-01	-19
1985-10-01	-23
1987-07-01	-33
1988-01-01	-78
2002-07-01	608
2002-10-01	378
2007-07-01	-859
2008-04-01	-586