Orange County added 3,300 jobs in April, when the unemployment rate fell to 7.4% from 8.2% in March and 8.5% a year earlier.

The relatively steep drop was aided in part by revised data for the earlier periods.

The county now has 1,387,500 jobs, according to the state Employment Development Department. It’s been adding jobs in small chunks since February, after cutting nearly 30,000 in January.

Education and health services had the largest increase in April, adding 1,500 jobs. Healthcare and social assistance accounted for 1,700 jobs, with some of the gain offset by a drop in jobs in educational services. The overall sector now has total of 162,400 jobs.

Professional and business services added 1,200 jobs, the next largest monthly growth. It had the biggest increase in job numbers over the year, gaining more than 11,000.

Temporary-help firms contributed to the increases. The industry now counts 254,400 jobs, which account for about 18% of Orange County employment.

The trade, transportation and utilities industry added 1,000 jobs last month. It has a total of 249,700 jobs.

That’s up 7,100 from last April. More than 90% of the year-over-year growth was concentrated in retail trade.

Construction had the largest monthly decline, losing 1,600 jobs in April. Last month's slash came after the job totals grew in February and stayed level in March. The construction segment had been cutting jobs for six straight months prior to the February uptick. It has 63,800 jobs now, down by 4,100 compared with April 2011.

Manufacturing cut 100 jobs, for a total of 154,700. It still has 2,400 more jobs compared with a year earlier.

The unemployment level in California was 10.5% last month, down from 11.5% in March and 11.5% a year earlier.

The national rate was 7.7%, down from 8.4% in March and 8.7% a year ago.