This little tidbit comes from MINI's own press release detailing the 2004 model year MINI Cooper and Cooper S:

It is difficult to draw a typical profile for a MINI buyer, although they are predominantly male with an above-average income and come from varying backgrounds and social environments. Over 80% of buyers are new to the BMW Group (i.e. do not own a BMW) and many cross-shop sports cars and performance coupes. Some unifying conditions seems to be a love of life, the appreciation of distinctive design and the desire to express themselves other than though obvious status symbols.