A once-in-a-decade job opportunity is just around the corner for jobless Americans who are struggling through the worst economic recession since the Great Depression.

Across the country, the 2010 census is ramping up efforts to hire 1.2 million temporary workers for the decennial head count, which begins in March.

Most of the jobs, about 700,000, will require knocking on doors for six to 10 weeks from May to July to find people who didn’t mail in their census questionnaires.

The massive hiring effort will require more than 3 million job applicants, and the U.S. Census Bureau is targeting unemployed workers to find them.

At a news briefing last week, Census Bureau Director Robert Groves said that his agency would advertise the job openings in unemployment offices as well as in the local media so that “everyone who needs a job knows about the job opportunities.”