I was wondering that too, but the end of the article does mention it: "the number of people who are homeless or vulnerably housed and who have also suffered a

I was wondering that too, but the end of the article does mention it: "the number of people who are homeless or vulnerably housed and who have also suffered a TBI may be as high as 61 per cent -- seven times higher than the general population." So it sounds like the rate in the normal population is about 8%, but that's probably men and women. Even if it was entirely men that had it (unlikely), that would put the incidence in the general population of men at 16%, significantly lower. And that rate includes the ones that end up homeless.