A quick search turned up a paper on Netherlands (population 16.77 mil): ... 9,200 sustain serious injury in a bicycle crash. A third of these seriously inj

A quick search turned up a paper on Netherlands (population 16.77 mil): ... 9,200 sustain serious injury in a bicycle crash. A third of these seriously injured bicycle casualties are diagnosed with head or brain injuries (32%) http://www.swov.nl/rapport/Factsheets/UK/FS_Bicycle_helmets.pdf http://www.swov.nl/rapport/Factsheets/UK/FS_Bicycle_helmets.... Showing 211 cyclists have a serious head injury per billion km cycled... Discussion: http://www.aviewfromthecyclepath.com/2010/08/brain-injuries-and-dutch-cyclist.html http://www.aviewfromthecyclepath.com/2010/08/brain-injuries-... Edit: accounting