For reasons known only unto itself, the NPD group saw fit Tuesday to issue a press release reporting on U.S. sales of tablets excluding the market’s 400-pound gorilla: Apple’s (AAPL) iPad.

“If you look at the tablet market without Apple there are a number of high-profile brands vying for that number two spot,” said NPD vice president of industry analysis Stephen Baker. “According to NPD’s Consumer Tracking Service, 76 percent of consumers who purchased a non-Apple tablet didn’t even consider the iPad, an indication that a large group of consumers are looking for alternatives, and an opportunity for the rest of the market to grow their business.”

Well, maybe, although how big an opportunity that represents is open for debate.

Apple doesn’t break out U.S.-only sales figures, but in the last 9 months it sold more than 25 million iPads and took in $15.75 billion.

In the first 10 months of 2011 the iPad also-rans sold a total of 1.2 million tablets in the U.S. and took in only $415 million in retail revenue.

Moreover, the only tablet besides the iPad that was generating any real consumer interest in November, according to a ChangeWave survey released Monday, was Amazon’s (AMZN) Kindle Fire — a device not included in NPD’s report.

“Importantly,” the ChangeWave press release added, “with the exception of the Samsung Galaxy Tab (4%) no other manufacturer is garnering more than 1% of future tablet demand among consumers.”

Making matters worse — or better, from Apple’s point of view — is the fact that the ChangeWave survey was largely concluded before the first wave of Kindle Fire reviews appeared. See here for how those turned out.