The total collision rate in the dynamically hot region that is interior to the observed belt's inner edge as a function of target planetesimal radius, assuming that the cs1 and cs2 events were caused by target progenitors ≥100 km in radius. For a given radius on the x-axis, the collision rate is the collision rate for target planetesimals greater than or equal to that radius. For example, the corresponding collision rate for a planetesimal with a radius of 50 km on the x-axis is the collision rate for target planetesimals with radii ≥50 km.