WASHINGTON — The Internal Revenue Service reminds taxpayers that they have one week remaining until the April 18 filing deadline and that they can use IRS Free File to do their taxes or file an extension.

As of March 25, the IRS has received more than 82 million individual income tax returns, which is 58 percent of the 141 million returns expected this year. The IRS has received about the same number of returns so far this year as it did at this time last year, while processing of returns is up 3 percent from the same time last year.

Numerous economic recovery tax credits are also still available. The IRS reminded taxpayers that for some credits, such as the Making Work Pay Credit, individuals must claim the $400 ($800 for married couples) in order to receive it. (Use Schedule M to calculate your Making Work Pay credit.)

Usually, 20 to 25 percent of all taxpayers file in the final two weeks of the tax season. And, usually, about 7 percent of taxpayers seek a six-month extension to file.

Taxpayers have an extra weekend to file this year because of a District of Columbia holiday. The deadline for 2011 is Monday April 18, instead of April 15.