%of total accidents is amost meaningless. % of accident deaths or even %of totaled cars would be a much better indicator. A parking lot fender bender is vary different than an 80MPH head on collision.

Also, even if speeding is not the direct cause of an accident it increases the damage resulting from an accident.

PS: It has been estimated that hard limiting private vehicles to 40MPH would have saved over 2 Million lives in the US. Not that I am promoting such a low speed limit but people really don't understand the dangers of speed. Every year after 1945 at least 30,000 people died with a peak well over 50,000.