Nhtsa estimates that aggressive driving accounts for about of all crashes and about of the resulting fatalities

The answer to this question is: one-third; two-third
When doing agressive driving, our brain tend to has delayed response towards our surrounding. 
This situation will improve the chance of collision if we have to face sudden movement from other cars on the street. In most cases, the agressive driving behavior is directly correlated with stress that is caused outside the road.