NEW YORK (CNNMoney.com) - If you haven't filed your taxes yet, join the crowd.

The Internal Revenue Service said it is expecting 134.1 million returns to be filed this tax season, but so far it has only received 87.7 million as of Friday, April 7.

The federal tax filing deadline this year is Monday, April 17. But if you live in Maine, Maryland, Massachusetts, New Hampshire, New York, Vermont or the District of Columbia, your tax filing deadline will be Tuesday, April 18. That's because Patriot's Day falls on the 17th and it's a state holiday in Massachusetts, where federal returns from the states listed are processed through a center in Andover. That center will be closed for the holiday.

In the states affected and in D.C., the filing deadline for state and local returns is also extended to April 18, according to H&R Block.

If you need a lot of extra time to file, you can request an automatic 6-month extension by April 17 (or 18 if you're affected by the Patriot Day holiday). Keep in mind, though, when you're granted an extension, it's just an extension to file. It's not an extension to make payments. So if you owe money to the IRS, you'll need to send payment along with your request for an extension. Otherwise, you will be subject to interest and penalties on the amount owed

Of course, if you're among the taxpayers expecting refunds, there is some incentive for to getting your taxes done as soon as possible.

The IRS said that the average refund for the week ending April 7 is up nearly 5 percent from a year earlier, to $2,290 from $2,189.

Many more taxpayers are choosing to e-file, which means they will get their refund in half the time. Returns e-filed from home computers is up almost 17 percent over last year's figure, according to the IRS.

"Each year, we are seeing more taxpayers choosing e-file, with the highest growth belonging to those who file from a home computer," said IRS Commissioner Mark Everson.

According to the latest Principal Financial Well-Being Index, people plan on being more responsible than usual with their refunds.

Fewer workers said they'll splurge on big ticket items (7 percent in 2006 down from 16 percent in 2003) and more people said they would save and invest their refund in 2006 (38 percent, up from 31 percent).

"Tax time is a great time to take any refund you receive and invest in your future either by opening up an IRA account, or increasing the deferrals in your 401(k) plan." Dan Houston, senior vice president of the Principal Financial Group, said in a statement.

"What's very encouraging today compared to a few years ago is that American workers are increasingly demonstrating a discipline for saving and investing their hard earned dollars, and are less likely than in the past to say they will run out and turn it in for a plasma TV for example."

The Principal Financial Group commissioned Harris Interactive to conduct an online study of 1,374 full- and part-time employees of small and midsized U.S. businesses between Jan. 31 and Feb. 8, 2006.

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