Among the new city folk: Burlington, Vt., Casper

Three of every 4 Americans now live in metropolitan areas, the Census Bureau reports. The designation of 36 additional population centers by the Office of Management and Budget added 4.5 million people to the nation's metropolitan area total, the bureau said. The centers, known as Standard Metropolitan Statistical Areas, were identified on the basis of 1980 census figures.

There are now 318 SMSAs in the 50 states. Each state has at least one, now that Burlington, Vt., and Casper, Wyo., have been added to the list.

The census showed that 169,405,018 people live in metropolitan areas -- 67.9 million in the central cities and 101.5 million in the suburban rings. Almost 57.1 million lived in nonmetropolit an areas.