DETROIT – Ten years ago, critics said a premium-priced B-car would never sell in the U.S. But Mini just marked its best sales year ever in 2011, logging 57,000 sales, a 26% increase over 2010.

The auto maker produced its 2-millionth vehicle in 2011 and delivered 285,000 units globally just last year, representing a 22% gain over prior-year. But in an odd twist on the original criticism that a small car never would do well in a country where giant SUVs are king, America is Mini’s biggest market.

The promise of continued growth has the BMW unit making plans to add 15 dealers to its U.S. dealer count of 110.

“With all these new dealerships to fill, we’re hard at work creating even more exciting, inventive and irresistible Minis for you,” Ian Robertson, BMW executive in charge of sales and marketing, says here at the North American International Auto Show.

Mini already offers five different vehicles in addition to the standard original 2-door hardtop. The latest is a convertible version of the new Mini Cooper Coupe. Still other versions are in the works, including another truck-like vehicle to go with its popular Countryman cross/utility vehicle.