BOSTON -- It may sound spooky, but a national Halloween costume retailer says it can predict the outcome of the presidential election based on the number of presidential candidate masks it's selling.

Spirit Halloween said it has picked the winner in the past three presidential elections days before the general election results were in.

The Spirit Halloween Presidential Index measures sales of the masks and in 2004, sales were 65 percent to 35 percent for George W. Bush over John Kerry.

In 2000, more revelers again purchased Bush masks, with Bush sales at 57 percent to 43 percent for Al Gore.

In 1996, however, Bill Clinton masks were snapped up 71 percent to Bob Dole's 29 percent.

What's the forecast this year? Spirit says so far the mask factor is looking good for Obama. After the first month of Halloween sales this year (Aug. 30 to Oct. 3) Obama is leading sales 67 percent to McCain's 33 percent.

“It’s no coincidence that presidential elections take place just days after Halloween, when the mask factor has its greatest impact,” said Steven Silverstein, president and CEO of Spirit Halloween. “The Spirit Halloween Presidential Index is a remarkably consistent and accurate predictor of the next president. It’s eerie.”

On a state-by-state basis, Spirit said, McCain is ahead only in Oklahoma. Arizona, Indiana, Kentucky, South Dakota and Vermont were tied or undecided. In most states, Obama is currently in the lead by a wide margin.

The election is still a month away, however, and Spirit said the highest volume of mask sales come in the last one to two weeks before Halloween.

Each week, McCain has been slowly closing the gap between himself and Obama in terms of mask sales, Spirit said.

Spirit Halloween is the largest seasonal Halloween retailer in the country with more than 600 locations in strip centers and malls across the United States and online.