Thats a bit enigmatic......
I am aware of information in papers that may be published. The OP includes;
But, if a FOI request was submitted to the companies that manufacture helmets requesting then to state in percentage terms how many deaths due to head injury wearing a helmet would prevent in comparison to not wearing a helmet, would
The question is understandable, but it also has weaknesses. It is looking at percentage head injury deaths. Take as an example, Porter 2016 report in the US detailed that cyclists wearing helmets had more than twice the odds of suffering an injury than cyclists not wearing helmets. The report’s Figure 1 shows the percentage injured among wearers and non wearers in the previous two years. The percentage injured for wearers was 2.81 times higher than for non-wearers.
Porter AK, Salvo D, Kohl HW, Correlates of Helmet Use Among Recreation and Transportation Bicyclists, AJPM 2016. https://uthealth.influuent.utsystem.edu ... ation-bicy
Assuming helmet wearing had a lower rate of deaths due to head injury, say 40% v 60% for non-wearers, based on Porters findings, deaths to helmeted could still be higher in number relative to non-wearers?
say 1000 accidents for non-wearers, say 6 deaths, say 2800 accidents for wearers, say 11 deaths, due to head injury.
Some worldwide data is available, http://www.parliament.wa.gov.au/parliam ... enDocument
if you look at the submission to the WA Inquiry it provides a comparison of deaths from countries with helmet laws v those without. see page 12