Interesting stats there.
The obvious one, which most of us no doubt have not considered, greatest number of head injuries (pro rata, I imagine) is that of car drivers and passengers. Myself, I religiously wear a helmet. Down to common sense, really.
Specialized 2019 range of helmets have option of ANGi device fitted, higher end helmets come with it while cheaper ones have mounting point for it. If ANGi detects a crash it rings your phone via bluetooth and iRide app, if you don't answer it will send emergency message with our location to friends and family. Ideal for solo MTB riders. If phone coverage is known to be patchy you can specify return time. The website will send a notification to friends/family if you don't return, along with last gps coordinates until coverage was lost.
NB ANGi can be fitted to any helmet but only Specialized ones have been tested with it. Price is USD50.
I've had a few close calls in the last few months, the last one I had to ride across the opposite side of the road to avoid a car coming out of a junction. Worst offenders for me, are drivers reversing from driveways onto the road.
Subsequently I now use a helmet, Hi Vis , main bike lights and two extra flashing lights at the front and the back.
I look like a flying saucer coming up the road but, so far, no one has pulled out on me and traffic seems to give me a wider berth. You have to look after yourself and your bike these days.