President Miguel de la Madrid said the sharp drop in oil prices will force Mexico to renegotiate payment of its $96.4-billion foreign debt. In a series of speeches he said the decline in oil earnings "worries all us Mexicans." Mexico depends on oil sales for about 70% of its foreign earnings, which are used to buy needed imports and repay its foreign debts. About $27 billion of Mexico's loans are held by U.S. banks. Chief debt negotiator Angel Gurria met in New York with representatives of the nation's creditor banks Tuesday. Banking industry sources said Mexico might need $9 billion in outside financial aid this year.