Retail sales in the Washington metropolitan area grew at a healthier rate than sales in most other large cities, the Greater Washington Research Center said last week.

In its monthly newsletter MarkeTrends, the nonprofit organization said retail sales, adjusted for inflation, grew at an average 2.6 percent a year between 1980 and 1984. Unadjusted for inflation, sales in the area grew by 39 percent between 1980 and 1984.

"The growth confirmed the area's continued vitality, despite recent shifts in its economic base," MarkeTrends said.

The rate of growth in retail sales for the metropolitan area exceeded the growth recorded by Houston, Los Angeles, San Francisco and other large cities, MarkeTrend found. In fact, it said, only Boston -- where sales grew 51 percent for the four years -- and Dallas -- where sales increased by 45 percent -- topped the growth experienced here.

The greatest growth came from sales in restaurants and bars, where the increase was 45.2 percent between 1980 and 1983, the latest year for which figures were available. Close behind were automobile and automotive-parts retailers, who posted a 44.3 percent increase during that same period.

The smallest gain came at drug stores, where growth in sales was only 21.6 percent. General merchandise, food and home furnishings, furniture and appliance stores all registered growth around 30 percent.

The newsletter attributed the sharp sales increase at restaurants and bars to "the growth of the affluent singles population" whose members are above-average restaurant-goers. "Another is the increasing number of multi-earner households, which are more likely to patronize fast-food establishments than those with only one earner."

The newsletter also notes that Prince George's County was the most populous in 1984, with an estimated population of 675,600. However, it noted Fairfax County was close behind and could be "edging ahead."

The center said Arlington County is the leading jurisdiction in terms of per capita income ($20,917) and average annual pay ($24,537) for workers.

Lowest ranking on both counts is Prince William County, where per capita income is $12,562 and annual average pay is $14,625.