From MINIUSA PR:
Demand for MINI brand automobiles was exceptionally strong as the division celebrated its third anniversary in the U.S. on March 22nd. March sales were the best ever recorded, for 4,127 cars versus 2,857 in March 2004, an increase of 44 percent. First quarter sales of MINI automobiles increased 23 percent with sales of 10,184 over the 8,271 sold in the first quarter of 2004.
You can check a complete sales break-down (as always) via Ian from gbmini.net.