It’s still not clear what the root cause of the sudden unexpected acceleration in Toyotas is, but this article at least gives us an idea of how widespread the problem is. Toyotas for 2008 are between 10 and 16 times as likely to experience this problem as GM, which had the best ratio of number of cars sold to the number of complaints. The reason for the range between 10 and 16 is that Toyota received a significant jump in complaints due to media attention. Of course, Toyotas are generally rated as having higher reliability than GM cars. Also, not all of these incidents result in accidents. Therefore, it would be nice if there was a comparison of how often defects in cars from a given automaker cause an accident.

http://blogs.consumerreports.org/cars/2009/12/sudden-unintended-acceleration-sua-analysis-2008-toyota-lexus-ford-gm.html