The productivity of the bluegrass fields has kept LEXINGTON 's economy ticking over since 1775, though its lack of a navigable river always made its traders vulnerable to competition from Louisville. Eighty miles east of Louisville and ninety south of Cincinnati, Ohio, it still retains large numbers of fine antebellum houses. However, its current affluence dates from after World War I, when smoking caught on internationally and Lexington emerged as the world's largest burley tobacco market. Despite a population now exceeding 200,000, the city maintains an almost rustic atmosphere, with its most conspicuous activity the horse trade.