The nation's unemployment rate edged up 0.1 percent in December to 7.2 percent, but ended the year a full percentage point below the level of the previous December, the Labor Department reported yesterday.

The department said 3.2 million more people found jobs last year, bringing total civilian employment up to 106.3 million. The number of unemployed people dropped from 9.2 million in December 1983 to 8.2 million last month.

White House spokesman Larry Speakes said the figures reflected "a banner year" for the American work force and "strong and continuing healthy growth in the economy."

The civilian unemployment rate has varied between 7.1 percent and 7.5 percent since June. Last month's unemployment rate reflected an increase from November, but was less than October's rate of 7.3 percent and was lower than the 7.5 percent rate prevailing when President Reagan took office four years ago.

The nation's civilian unemployment rate rose to 10.7 percent, or more than 12 million jobless, near the end of the 1981-82 recession. Since then, the number of jobless persons has been reduced by 3.7 million, Janet L. Norwood, commissioner of the Bureau of Labor Statistics, said in testimony prepared for yesterday's hearing of Congress' Joint Economic Committee.

Norwood said two-thirds of the jobs created since the end of the recession have been in the service sector, but added that "in the goods-producing sector, very few industries had added more than the number of jobs lost during the recession."

The nation's overall unemployment rate, which includes members of the armed forces stationed in the United States, increased to 7.1 percent last month from 7.0 percent in November.

The number of employed people increased by 340,000 in December, but the number looking for jobs increased by 390,000, causing the slight increase from November's civilian unemployment rate.

"The pause in the expansion is completely over," said Donald Berson, chief financial economist of Wharton Econometrics, predicting "fairly strong growth in the first quarter" of this year.

Sen. William Proxmire (D-Wis.) was less comforted by the growth in jobs and expressed concern about an unemployment rate that has prevailed since June.

"We seem to have bottomed out at an unemployment level of about 7.2 percent. In my view, the outlook is not that good," said Proxmire, senior Democrat on the Joint Economic Committee.

Private economists, however, said December's increases in manufacturing and construction employment indicate strong growth in industrial production last month, a sign of healthy economic expansion.

Employment growth in December was widespread, according to the Labor Department report, with two-thirds of the industries surveyed showing employment expansion.

Berson said the "very strong increases" in manufacturing employment over the last four months "can be taken as a trend" and are important for general economic growth.

"It takes widespread increases in employment to sustain an expansion. . . . You can't have everybody working at K mart and Burger King," he said, referring to the service sector, which expanded by 95,000 jobs last month.

Construction jobs, after adjustment for seasonal variations, increased by 55,000 last month.

Manufacturing jobs increased by 85,000 to 19.8 million in December, and the average number of weekly hours rose by 0.2 hours to 40.7 hours.

"Manufacturers still apparently have sufficient confidence in the future to increase the number of hours worked," said Roger Brinner, chief economist at Data Resources Inc.

"The important number to focus on is employment growth," Brinner said. "With this kind of sustained employment growth, it would be impossible to engineer a downturn."

Brinner added, however, that unemployment could rise early this year to reflect the current level of economic growth. "Growth is not sufficiently rapid in early 1985 to hold employment at its current level," he said. "It will be a good year this year, but maybe not as good as some people in Washington expect."

December employment levels in five industries were even lower than at the end of the recession in November 1982, Norwood said, referring to mining, steel, tobacco, petroleum and coal, and leather.

The Labor Department also reported an increase in the number of "discouraged workers," those who say they want to work but have given up looking for a job. The department reported 1.3 million discouraged workers in the fourth quarter, up from 1.2 million in September. That figure reached a high of 1.8 million in late 1982.

Blacks continue to make up more than a proportionate share of the "discouraged," at 38 percent in the fourth quarter, Norwood said.

The general unemployment rate for blacks declined to 15 percent in December from 15.1 percent in November. But among black teen-agers, the group with the highest unemployment, the jobless rate rose to 42.1 percent last month from 41.2 percent the preceding month.

The unemployment rate for all teen-agers rose to 18.8 percent from 17.8 percent in November.