My intended point was that helmets are a huge factor in both fatalities and crippling injuries. This reference from helmets.org seems supporting:

"About 540,000 bicyclists visit emergency rooms with injuries every year. Of those, about 67,000 have head injuries, and 27,000 have injuries serious enough to be hospitalized."

"Bicycle crashes and injuries are under-reported, since the majority are not serious enough for emergency room visits. 44,000 cyclists were reported injured in traffic crashes in 2006."

"1 in 8 of the cyclists with reported injuries has a brain injury."

So my math says there were 5500 brain injured cyclists in 2006 compared with 770 fatalities (of which 2/3rds were directly related to traumatic brain injuries).

So roll your eyes if you will, just wear a helmet.