YEUTTER SEEKS STRONGER TAIWAN, S.KOREA CURRENCIES U.S. Trade Representative Clayton Yeutter said he hoped the U.S. dollar would continue to decline in relation to the currencies of Taiwan and South Korea as a way to improve the U.S. trade picture. Testifying before the House Appropriations subcommittee which must approve his agency's 1988 budget, he said, "In my judgment economic factors justify a continued decline." Asked by a committee member if he expected a further decline, and how much, Yeutter said the Taiwan and South Korean currencies should be adjusted to reflect "positive factors" in their economies.