Buick, formally the Buick Motor Division, is an upscale automobile brand of the American manufacturer General Motors (GM). For much of its existence in the North American market, Buick has been marketed as a premium automobile brand, selling luxury vehicles positioned above GM's mainstream brands, e.g. Chevrolet, while below the flagship luxury Cadillac division. Buick-branded vehicles are also known for reliability, ranking high for reliability in Consumer Reports' brand reliability rankings. Buick has the distinction of being the oldest active American marque of automobile, and was the company that established General Motors in 1908. Before the establishment of General Motors, GM founder William C. Durant had served as Buick's general manager and major investor. Buick also has the distinction of being the first automobile maker in the world to equip its cars with overhead valve engines, which it did starting in 1904. In 2015, Buick sold 1,231,941 vehicles, a record for the brand. The main market is in China, where 80% of Buick-branded automobiles are sold. Buicks are also sold in the United States, Canada, and Mexico. Since restructuring in 2009, GM has also started to share technology, vehicles and development between Buick and GM's European Opel division.