From BMW Group PressClub USA:

MINI USA reported sales of 4,425 automobiles, a decrease of 13.4 percent from the 5,111 cars sold last year.  Year-to-date, MINI USA also reported sales of 29,704 automobiles, a decrease of 3.8 percent from the 30,868 units sold last year.  The drop in sales was again affected by the Cash for Clunkers program that took place in July and August of 2009 and boosted sales volume.
MINI sales will gain momentum as the year progresses due the updated 2011 model year vehicles arriving at dealerships in two weeks.  Additionally, the brand is seeing significant customer interest in the Countryman as MINI dealers have just begun taking orders for the new model coming out in January 2011..

August 2010 August 2009 change year-to-date 2010 year-to-date 2009 change
4,425 5,111 -13.4% 29,704 30,868 -3.8%

See MINI sales in the USA by month.