WASHINGTON (February 5, 2010)--The U.S. is spending $2.5 million to advertise during the Super Bowl to promote the census, which Census officials say will be a good investment if it gets people to mail back their census forms.

But not everyone agrees.

Sen. John McCain, R-Arizona, tweeted this week that the government "shouldn't be wasting $2.5 million taxpayer dollars to compete with ads for Doritos."

A recent poll found nearly 1 in 5 residents said they may not fill out the forms.

The government relies on the census not only to learn about Americans and their lives, but also to parcel out federal dollars and to determine the number of U.S. House seats representing each state.

The census officially began last month in rural Alaska, and most residents of the U.S. will receive their forms by mail the week of March 15.