Fill out your Census form and win an iPod? A Starbucks gift certificate? Cash?

Doing your civic duty would literally pay off if the Commerce Department and Congress decide to dangle prizes to get people to answer Census questionnaires in 2010.

The Census Bureau is looking at ways to increase responses, including the use of prizes as an incentive, says spokesman Stephen Buckner.

It's not the first time the idea has come up. The Census Bureau explored launching sweepstakes in the 1990s. It rejected the plan partly because of concern that it would cheapen the national population count mandated by the Constitution every 10 years. It's not clear if using budget money to fund prizes is even legal.

Nevertheless, the concept is resurfacing for the 2010 Census because of concerns the response rate may be hurt by mounting fear and suspicion of government, says Census historian Margo Anderson. More communities are cracking down on illegal immigrants and the war on terrorism has prompted surveillance measures, including wiretapping.

The Census is crucial because it is used to redraw congressional districts and allocate billions in federal funds. In 2000, even after door-to-door visits by Census employees and a paid advertising campaign, only 67 percent of households responded.

At a hearing last month, Sen. Tom Carper, D-Del., chairman of a subcommittee that oversees the Census, suggested the bureau take a fresh look at how to increase the response rate.

Sen. Tom Coburn, R-Okla., also a member of the subcommittee, says offering prizes would be cheaper than chasing people who don't return their questionnaires. It costs $75 million to increase the response rate by 1 percentage point, Census data show.

Rep. Carolyn Maloney, D-New York, a member of a House Census committee, says incentives would "turn the Census into a lottery ticket."