U.S. tablet sales, excluding iPad sales, reached 1.2 million units for the first ten months of 2011 according to a recent report from the NPD Group.

Surprisingly, HP, which released its WebOS powered Touchpad tablet in July and cancelled it in August, was the number one seller with a 17% market share or just over 200,000 units.

Rounding out the top five in marketshare after Apple were Samsung (16%), Asus (10%), Motorola and Acer (9% each).

By comparison, Apple sold the Apple iPad sold 11.12 million iPads in the previous quarter alone.

NPD says tablet hardware sales have accelerated throughout the year with each quarter performing better than the prior quarter. Third quarter sales were two times that of second quarter sales and second quarter sales were three times better than first quarter.

“If you look at the tablet market without Apple there are a number of high-profile brands vying for that number two spot,” said Stephen Baker, vice president of industry analysis at NPD. “The market is filled with long-time PC and phone brands as well as low-cost entrants.”

PC manufacturers are dominant in the tablet space, as four of the top five tablet brands already have a strong U.S. consumer PC presence. Only two of the top five brands play in the smartphone market.

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