Individual life insurance sales rebounded last year for Government Employees Life Insurance Co., as earnings rose slightly to a record level. Profits from operations rose slightly at Criterion Insurance Co. and declined slightly at Avemco Corp., the insurance firms reported yesterday.

Government Employees Life earnings were $8 million ($1.79 a share) compared with $7.8 million ($1.75) in 1977, reflecting small gains in both investment and premium income.

Individual life policy sales rose to $173 million from $154 million, a significant recovery that followed a 44 percent decline in sales during 1976 and 1977, which the company had attributed to adverse publicity about the previous woes of an automobile insurance affiliate, Government Employees Insurance Co.

The life company's direct-mail sales efforts of previous years were closely tied to all clients of the Government Employees group of firms and when the auto firm's customers were reduced, the life insurance company's sales efforts were hampered.

Last year's rebound in sales, which was helped by new marketing programs, brought total insurance in force at year's end to $2.325 billion compared with $2.3 billion a year ago.

Criterion Insurance, another Gov ernment Employees firm that insures automobiles for drivers considered greater risks than those insured by Geico, posted 1978 earnings of $5.8 million ($3.96 a share) compared with $5.7 million ($3.91) in 1977, not counting extraordinary items. Net income was $7.1 million ($4.86 a share) vs. $8.6 million ($5.87).

Profits from underwriting auto policies fell by $1.4 million to $2.25 million in 1978 while income before investment gains or losses and extraordinary items rose to $5.8 million from $5.7 million.

In the fourth quarter alone, Criterion's earnings before extraordinary income were $2 million ($1.35 a share) compared with $2 million (85 cents) and underwriting income rose substantially to $1.5 million from $388,000. Net premiums for the year rose $622,000 to $70.4 million.

Criterion's directors voted to increase the quarterly dividend rate to 20 cents a share, payable March 30 to owners of record March 6. Previously, the company paid 15 cents on Dec. 29.

Avemco Corp. reported 1978 profits of $2.2 million (88 cents a share) compared with $2.5 million (91 cents) on 268,000 more shares outstanding the previous year. Fourth-quarter profits dipped to $771,000 (31 cents) from $859,000 (34 cents).

The national aviation insurance and finance services firm, based in Bethesda, said an unusually high number of aviation accidents last year reduced insurance underwriting profits. In 1977, Chairman Arnold Johnson noted, the frequency of accidents had been much lower.

Avemco's pre-tax underwriting profits still exceeded $1 million in 1978, Johnson said. Gross premiums were a record $19.2 million, a gain of $2.2 million from 1977. Total revenues rose to $16 million from $14 million.