And the USA is a huge part of this success. This was evident when BMW Motorrad USA released its December 2014 numbers. BMW says 1,232 motorcycles and maxi scooters were sold, compared to 1,101 in December 2013, showing an 11.9-percent increase in sales.The best selling model in December was the 2014 R1200RT, which arrives with the semi-water cooled Boxer engine transplanted from the R1200GS. BMW Motored says 207 R1200RTs were sold, helping drive growth of 17% in R-Series sales with 477 boxers sold compared to 408 a year ago.BMW Motored USA says 202 of its S1000RR superbikes were sold. Collectively, 254 S-series models were sold compared to 141 in December 2013.As a result, BMW Motorrad wrapped up 2014 with 14,945 retails, the best performance in more than decade and 5.4 percent ahead of last year. With an energized dealer network and three new models debuting in January, BMW Motorrad says it is well positioned to start 2015 with a bang.