Metropolitan Washington's economy grew at a faster rate between 1968 and 1976 than of the nation as a whole, according to new statistics complied by the Chesapeake & Potomac Telephone Co.

Updating an earlier study of gross metropolitan are product (GMAP), gross product (GNP) C&P reported that the city's economy has been stagnant since the mid-1960s.

All of the figures compiled measure total output of goods and services for the nine years, with metropolitan output rising at an average rate of 2.6 percent a year compared with 2.3 percent for the nation as a whole.

Total output for the are in 1976 was estimated at $18.5 billion, or 1.9 per cent of the entire national economy (up from 1.6 per cent in 1968).

The data show that the District's share of area output declined from 52 per cent in 1968 to 43 per cent last year. Meanwhile, government, services, finances, insurance, real estate and retail-wholesale trade were the principal components of the economy.

Although the telephone company figures show the Maryland suburbs with a larger economic base than that of Northern Virginia (31 per cent of GMAP vs. 36 per cent. Virginia has been increasing more rapidly and projections indicate that the two suburban economic will be of equal size by 1985.

The largest single element in the District's economic decline compared with the suburbs has been retail and wholesale trade, dropping from a 43 per cent of GMAP in 1962 to 26 per cent in 1976.

Finance-insurance-real estate is the only economic sector where D.C. continues to dominate the suburbs but that share declined from 70 per cent to 56 per cent in the nine years measured.

C&P's business research division published the data in Sept. 26 issue of "Business in Washington."

Other conclusions of the C&P study included:

Area economic growth was 6.6 per cent annually from 1960 to 1968 compared with 2.6 per cent a year in 1968-1976. The principal factor in slow down was found to be lack of growth in the District itself, coupled with national recession.

The federal government will continue at the core of the Washington economy although the D.C. share of area government activity declined to 49 per cent from 53 per cent.