CHICAGO (CBS) — The tax deadline is approaching, and millions of taxpayers still haven’t filed their income tax returns.

“Most procrastinators are those who don’t want to part with their check, because they owe and aren’t getting a refund,” said IRS Spokesman Michael Devine.

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Devine says filing electronically is the way to go. In fact, e-filing is up 6 percent over last year in Illinois.

“The chances of making an error on an electronically prepared return is less than 1%, the error rate on paper returns goes as far as 20%, so if you’re worried about making a mistake, then you want to do it electronically,” he said.

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Devine says the most common mistakes involve Social Security numbers. Either people put them in wrong, they forget to put them in, or the name and Social Security numbers don’t match. Arithmetic errors are also common.

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“People take the wrong number from the wrong table. They add or subtract wrong. So if you’re doing it by paper, you’ve got a bigger chance of making an error that’s going to generate an error by the IRS,” said Devine.

Up to 30 percent of filers wait until the last minute.

Devine says if think you’ll miss the April 17 deadline, you can request a 6 month extension.

Taxes are due on a Tuesday this year because the April 15 is a Sunday and April 16 is Emancipation Day in the nation’s capitol, which is a federal holiday.

In Illinois, 3.8 million returns have already been processed.

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