I wouldn’t know the demographics, I would imagine it’s probably 60% men. I have to say I never feel for the sternum and never have. It’s very obvious on a real person where you have to put your hands, slightly more difficult on a child.
Under wires would make no difference to how far you push down, it is about a third of the depth of the body, you have to press hard to do that so a little thing like an underwire would not even feature.
Strangely enough most of my survival to hospital cases have been women although I’m not sure why.
To think that London, or anywhere else for that matter, does not belong to any one demographic
Lack of public toilets in towns.