ROCHESTER, WIS. — Living costs vary widely within the 12 European Community nations, according to Runzheimer International, consultants for relocations. Based on a United States family of four with a base salary of $75,000, the comparative costs in Athens for food, rent, and other living costs would total $71,000 and in Paris $116,000. These were the least and most expensive cities, respectively, of the 12 cities included in the study. Following Paris were Madrid, London, Copenhagen, and Milan - all with totals higher than $100,000. Living costs in Luxembourg, Dublin, Lisbon, Amsterdam, Brussels, and Frankfurt were under $90,000.