From BMW Group PressClub USA:

MINI USA reported sales of 4,884 automobiles, an increase of 18.3 percent from the 4,128 cars sold last year.  Year-to-date, MINI USA also reported sales of 34,588 automobiles, a decrease of 1.2 percent from the 34,996 units sold last year.

September 2010 September 2009 change year-to-date 2010 year-to-date 2009 change
4,884 4,128 18.3% 34,588 34,966 -1.2%

See MINI sales in the USA by month.